Critical Reasoning

[RiyaR]

For several years, per capita expenditure on prescription drugs in Voronia rose by fifteen percent or more annually. In order to curb these dramatic increases, the ministry of health prohibited drug manufacturers from raising any of their products' prices. Even though use of prescription drugs did not expand after this price freeze, per capita expenditure for prescription drugs continued to increase by a substantial percentage each year.
Which of the following, if true, most helps to explain why the ministry's action did not achieve its goal?
A. After price increases were prohibited, drug manufacturers concentrated on producing new medications to replace existing products
B. The population of Voronia rose steadily throughout the period.
C. Improvements in manufacturing processes enable drug manufacturers to maintain high profit levels on drugs despite the price freeze.
D. In addition to imposing a price freeze, the government encouraged doctors to prescribe generic versions of common drugs instead of the more expensive brand-name versions
E. After price increases were prohibited, some foreign manufacturers of expensive drugs ceased marketing them in Voronia.


The answer is A....But I marked B. Why is B wrong?

[GMATGuruNY]

For several years, per capita expenditure on prescription drugs in Voronia rose by fifteen percent or more annually. In order to curb these dramatic increases, the ministry of health prohibited drug manufacturers from raising any of their products' prices. Even though use of prescription drugs did not expand after this price freeze, per capita expenditure for prescription drugs continued to increase by a substantial percentage each year.
Which of the following, if true, most helps to explain why the ministry's action did not achieve its goal?
A. After price increases were prohibited, drug manufacturers concentrated on producing new medications to replace existing products
B. The population of Voronia rose steadily throughout the period.
C. Improvements in manufacturing processes enable drug manufacturers to maintain high profit levels on drugs despite the price freeze.
D. In addition to imposing a price freeze, the government encouraged doctors to prescribe generic versions of common drugs instead of the more expensive brand-name versions
E. After price increases were prohibited, some foreign manufacturers of expensive drugs ceased marketing them in Voronia.

Fact 1: Manufacturers of prescription drugs were prohibited from RAISING any of their products' prices.
Fact 2: PER CAPITA expenditure for prescription drugs continued to increase by a substantial percentage each year.

The correct answer choice must explain how both facts can be true at the same time.

A: After price increases were prohibited, drug manufacturers concentrated on producing new medications to replace existing products.
Implication:
Manufacturers set high prices for these NEW medications -- a clever way to increase revenues WITHOUT RAISING the prices of already-existing medications.
As a result, per capita expenditure for prescription drugs continued to increase by a substantial percentage each year.

The correct answer is A.

B: The population of Voronia rose steadily throughout the period.
PER CAPITA expenditure = (total amount spent)/(total population).
B indicates that the denominator of this fraction increased.
Since a bigger denominator implies a smaller fraction, the result of a population increase could be a DECREASE in per capita expenditure -- contradicting Fact 2.
The correct answer choice cannot contradict the passage.
Eliminate B.