Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

Kaplan 1

Expert replies
by mals24 » Tue Nov 25, 2008 1:42 pm
It is difficult to find the precise causes of any disease resulting from B-vitamin deficiencies. For example, it was known that being deficient in all the B-vitamins was sufficient to contract the disease beriberi, and also that beriberi was always accompanied by a deficiency of vitamin B1. However, recent human volunteers on special diets designed to lack only vitamin B1 did not contract the disease.
Which of the following if true best explains the results above?

A. Individuals whose diets lack vitaminB1, will contract beriberi only if they have a generally unhealthy diet.
B. A deficiency in vitamin B1, is not necessary to contract beriberi.
C. Beriberi can be cured by any variety of B vitamin supplements.
D. Beriberi is caused by deficiencies in a combination of B-vitamins
E. Deficiencies in the B vitamins have widely varying effects on different individuals, so that specific diseases cannot be adequately identified.
Join the discussion
Source: — Critical Reasoning |

by Tryingmybest » Tue Nov 25, 2008 1:50 pm
Initially picked B but IMO D


OA PLZ?
Last edited by Tryingmybest on Tue Nov 25, 2008 4:05 pm, edited 2 times in total.
Join the discussion

by schumi_gmat » Tue Nov 25, 2008 2:30 pm
Arg: lack of defeciencies in vitamin B causes Beri beri which causes defeciency b1

Conclu: Humans lacking B1 did not contract beri beri

This is possible only if beri - beri is caused by combination of vitamin B

Hence D
Join the discussion

by gkammaje » Tue Nov 25, 2008 2:33 pm
D ?
beriberi is always accompanied by a deficiency of vitamin B1 -but deficiency of vitamin B1 (and only vitamin B1) does not always casue berberi. It is necessary but not sufficient

hence D.
Beriberi is caused by deficiencies in a combination of B-vitamins
Join the discussion

by mals24 » Wed Nov 26, 2008 2:20 am
OA D
Join the discussion

by nicolette » Fri May 13, 2016 1:29 am
It seems to me that the right answer is D
Join the discussion

by vanessa.m » Fri May 13, 2016 1:32 am
In my opinion A is the most logical one.
Join the discussion