The correct answer is option 'C' - SLR (Statutory Liquidity Ratio).

Explanation:
The Reserve Bank of India (RBI) uses various quantitative and qualitative measures to control credit in the economy. These measures are implemented to regulate the flow of credit and manage inflation.

Qualitative credit control measures are non-quantifiable measures that are aimed at influencing the credit behavior of banks and financial institutions. These measures are more flexible and discretionary compared to quantitative measures. They include:

a) Capital Rationing:
Capital rationing is a qualitative credit control measure where the RBI restricts or limits the amount of capital that banks can allocate for lending purposes. By imposing capital limits, the RBI ensures that banks have sufficient capital to meet regulatory requirements and maintain their financial stability. This measure helps in controlling excessive lending and prevents the banks from taking excessive risks.

b) Moral Suasion:
Moral suasion is a persuasive technique used by the RBI to influence the lending behavior of banks. It involves informal communication, discussions, meetings, and directives to convince banks to adopt certain credit policies. The RBI uses moral suasion to encourage banks to increase or decrease their lending activities in line with the monetary policy objectives.

c) SLR (Statutory Liquidity Ratio):
SLR is a quantitative credit control measure and not a qualitative measure. It refers to the percentage of a bank's net demand and time liabilities (NDTL) that it is required to maintain in the form of liquid assets such as cash, gold, government securities, etc. The purpose of SLR is to ensure the solvency and liquidity of banks. By adjusting the SLR, the RBI can control the flow of credit in the economy. An increase in the SLR reduces the funds available for lending, while a decrease in the SLR expands the lending capacity of banks.

d) Margin Requirement:
Margin requirement is a qualitative credit control measure that pertains to the lending against specific securities. The RBI can impose higher margin requirements, i.e., increasing the proportion of collateral that borrowers need to provide, to restrict the availability of credit for certain types of loans. Higher margin requirements reduce the amount of loans that can be availed against a given collateral, thus limiting credit expansion.

In conclusion, the correct answer is option 'C' - SLR, as it is a quantitative credit control measure rather than a qualitative measure.