What compound is produced when (CH₃) ₂CHCH₂Br is subjected to the following sequence of steps?
1) Mg, Et₂O 2. CO₂

A) 2-methylpropanoic acid
B) 3-methylpropanoic acid
C) 2-methylbutanoic acid
D) 3-methylbutanoic acid
E) 2-methylhexanoic acid