1. The problem statement, all variables and given/known data 2. Relevant equations Since question says the current is always continous, so overlap is always there. So option B is incorrect. Also since firing angle is increased from 0 to 45, the overlap angle will reduce. So it'll be less than 45. So option A is incorrect. 3. The attempt at a solution I don't know how to eliminate either C or D. Book says answer is C. But how?