Data Sufficiency

Beginning in January of last year, Carl made deposits of $120 into his account on the 15th of each month for several consecutive months and then made withdrawals of $50 on the 15th of each of the consecutive months of last year. There were no other transactions. If the closing balance of Carls account for May last year was 2600$ what was the range of monthly closing balances of cARLS account last year?

1) Last year closing balance of Carl's account for April was less than $2625
2) Last year closing balance of Carl's account for June was less than $2675

OA is C

Request someone to explain. I am unable to understand the OG explanation

Here is an explanation https://www.beatthegmat.com/og-12th-ed-d ... 70373.html

Beginning in January of last year, Carl made deposits
of $120 into his account on the 15th of each month
for several consecutive months and then made
withdrawals of $50 from the account on the 15th of
each of the remaining months of last year. There were
no other transactions in the account last year. If the
closing balance of Carl's account for May of last year
was $2,600, what was the range of the monthly
closing balances of Carl's account last year?

(1) Last year the closing balance of Carl's account for April was less than $2,625.
(2) Last year the closing balance of Carl's account for June was less than $2,675.

Did nt understand the question and the explanation given in OG. Please help

May = 2600.

Statement 1: Last year the closing balance of Carl's account
for April was less than $2,625.
If 120 was deposited in May, then April = 2600-120 = 2480.
If 50 was withdrawn in May, then April = 2600+50 = 2650.
Since April < 2625, we know that a deposit of 120 was made in May, implying that 120 was deposited every month January through at least May.
Thus, we can determine the balance of every month January - April:
April = 2480, March = 2480-120 = 2360, etc.
No information about June - December.
Insufficient.

Statement 2: Last year the closing balance of Carl's account
for June was less than $2,675.
If 120 was deposited in June, then June = 2600+120 = 2720.
If 50 was withdrawn in June, then June = 2600-50 = 2550.
Since June < 2675, we know that a withdrawal of 50 was made in June, implying that 50 was withdrawn every month June - December.
Thus, we can determine the balance of every month June - December:
June = 2550, July = 2550-50 = 2500, etc.
No information about January - April.
Insufficient.

Statements 1 and 2 combined:
Statement 1 tells us the closing balances January - April.
The question stem tells us the closing balance in May.
Statement 2 tells us the closing balances June - December.
Combining the information above, we can determine the closing balance of every month and determine the range for the whole year.
Sufficient.

The correct answer is C.