Simplfy
b - [b -(a+b) - {b - (b - a+b)} + 3a]
Options:
A) -a B) 2a C) 4a D) 0 E) 1
Explanation:   b-[b-(a+b)-{b-(b-a+b)}+3a]   =b-[b-a-b-{b-(2b-a)}+3a]   =b-[-a-{b-2b+a}+3a]   =b-[-a-{-b+a}+3a]   =b-[-a+b-a+3a]   =b-[-2a+b+3a]   =b-b-a   =-a   Option -a
<result>A</result>
Simplfy
b - [b -(a+b) - {b - (b - a+b)} + 3a]