Rewrite the following sentence in indirect speech- Teacher said to Ravi,” What is your name? 

Teacher asked Ravi _____. 

Indirect Speech is used to document some thing in our personal words. The given example is an example of Interrogative Questions. Indirect speech is formed by using 'ask' + question word + clause. The clause may have the question, in normal phrase order and with the important tense change. In this case, the easy present tense is given in clause. It might be modified to simple past tense. Indirect speech might be - Teacher asked Ravi what his name was. 

Thus, choice C is the right solution according to the rules.