The correct answer is C. Rs. 7.
Share capital account will be debited by the amount of share capital that is forfeited. In this case, the share capital is Rs. 10, but only Rs. 7 has been paid up. Therefore, the share capital account will be debited by Rs. 7.
Option A is incorrect because it is the amount of the share capital that is called up. Option B is incorrect because it is the amount of the share capital that is called up plus the premium. Option D is incorrect because it is the total amount of the share capital.