2a - b - [2b - {3c - (a - 3b + 3c)}] এর সরলমান কত?

A a

B a - b

C a + b

D b

Correct Answer: Option A

2a - b - [2b - {3c - (a - 3b + 3c)}]
= 2a - b - [2b - {3c - a + 3b - 3c}]
= 2a - b - [2b - 3c + a - 3b + 3c]
= 2a - b - [a - b]
= 2a - b - a + b
= a