What is the principal part of the underlined verb in the sentence? He flew across the country to visit his grandparents. A. past B. present C. present participle D. past participle

The verb, I assume, is "flew" and the tense is A. past. if it was any of the other options, "fly:  would be in a dfferent form : B. present he flies C. present participle he did something, flying D. past participle he has flown