Which one of the following is not an instrument of selective credit control in India?

1. Selective credit control measures are tools used by the central bank (RBI in India) to regulate the flow of credit to specific sectors or activities in the economy, unlike general credit controls (like Bank Rate, CRR, SLR) which affect the overall credit supply. 2. Regulation of consumer credit involves controlling the terms (like down payment, repayment period) for loans on consumer durables, thus influencing demand for specific goods. This is a selective measure. 3. Rationing of credit involves imposing limits or quotas on the credit provided by banks, overall or to specific sectors. This can be used selectively. 4. Margin requirements refer to the proportion of the loan amount that a borrower has to finance themselves when borrowing against securities. By varying margins for loans against specific commodities, the RBI can selectively discourage hoarding or speculation. 5. Variable cost reserve ratios is not a standard term for a monetary policy tool. It seems to incorrectly refer to Cash Reserve Ratio (CRR) or Statutory Liquidity Ratio (SLR), which are *general* or quantitative credit control instruments, not selective ones. Therefore, this is not an instrument of selective credit control.