Code Optimizer of Compiler actually reduces the code of a program.
Ex: x = 27 * 5 is transformed to x = 135
And Optimization phase also optimizes the code to reduce execution time.
Say, After Intermediate Code Generation phase if the program will looks like
x = b*c
y = x*v
z=y
then,Code Optimizer will take this code & transformed it into this:
x = b*c
z = x*v
So, option A) & B) both are Right.
Option (C) Both (A) and (B) is Correct.