Introduction:
In this scenario, C and D are partners in a firm sharing profits and losses equally. C withdraws a fixed amount of rupees 6000 at the beginning of each quarter. The interest on the drawings is charged at a rate of 6% per annum. In order to account for the interest on drawings at the end of the year, we need to pass necessary journal entries.

Journal Entry for Quarterly Drawings:
At the beginning of each quarter, C withdraws a fixed amount of rupees 6000. This withdrawal needs to be recorded in the books of accounts. The journal entry for quarterly drawings will be as follows:

Journal Entry:
C's Capital Account Dr. - 6000
To Bank Account - 6000

This entry records the withdrawal of cash by C from the bank and reduces C's capital account by the same amount.

Calculating Interest on Drawings:
To calculate the interest on drawings, we need to compute the average drawings made by C throughout the year. Since C withdraws a fixed amount of rupees 6000 at the beginning of each quarter, the average drawings can be calculated as follows:

Average Drawings = (6000 * 4) / 2 = 12000

The interest on drawings is charged at a rate of 6% per annum. Therefore, the interest on average drawings will be:

Interest on Drawings = Average Drawings * Rate of Interest
= 12000 * 6%
= 720

Journal Entry for Interest on Drawings:
At the end of the year, we need to pass a journal entry to record the interest on drawings. The journal entry will be as follows:

Journal Entry:
Interest on Drawings Account Dr. - 720
To C's Capital Account - 720

This entry debits the Interest on Drawings Account and credits C's Capital Account with the amount of interest on drawings calculated.

Conclusion:
In conclusion, to account for the interest on drawings at the end of the year, we pass a journal entry debiting the Interest on Drawings Account and crediting C's Capital Account with the amount of interest on drawings calculated. This helps in accurately recording the interest on drawings and adjusting the capital accounts of the partners accordingly.