An 80kg quarterback jumps straight up in the air right before throwing a 0.43kg football horizontally at 15m/s . how fast will he be moving backward just after releasing the ball? (this is not the question that is to be answered)

this is the question (that needs to be answered):
which of the following best describes why you can analyze this event using conservation of momentum?

a. the throwing action is quick enough that external forces may be ignored.

b. external forces don't act on the system during the jump.

c. conservation of momentum is always the best way to analyze motion.