Strength Reduction : Replace expensive operations with less expensive but equivalent operations.
For Example : Multiplication is more expensive operation than addition.
Shift operation is less expensive operation than Multiplication/Division.
2*3 CAN BE REPLACED WITH 2+2+2 .
OPTION A : We are replacing less expensive operation with more expensive operation which is not right. So Option 1 is incorrect.
Option B : We are replacing Multiplication (Expensive Operation) With Shift(Less expensive) . So this is OK
Option : C Both are equivalent
Option D: Replacing shift(Less Expensive) with Multiplication . This is Wrong
Correct Answer for This Question is B.