Is Manuel the one talking? (I) If so, it would be o.
Is somebody asking Manuel which ending he would use? (You) if so, it would be as.
Answer:
#1 voy
#2 son las cinco menos cuatro
Answer: I’m doing great “lo estoy haciendo genial”
Explanation: If you wanna ask them a question about how they are then say “I’m doing great how about you?”