CRR is a short form that shows up often in economics and banking exams, so it helps to break the term itself apart rather than just memorise it.
Cash Reserve Ratio directly controls how much a bank can lend, since a higher CRR locks away more cash and a lower CRR releases more cash into the system. This makes it a key lever the RBI pulls to control inflation and liquidity.
Let's summarize:
So the correct expansion of CRR is Cash Reserve Ratio, option (B).