B. and D. For the both I'm most likely sure
15% = 0.15
15% of 71.85 is equal 0.15*71.85 ≈ 10.78
Answer:
5040
Step-by-step explanation:
There are 7 options for the 1st song, 6 options for the 2nd song, 5 options for the 3rd song, 4 options for the 4th song, 3 options for the 5th song, 2 options for the 6th song, and 1 option for the 7th song. We get:

(<em>Note: when you have a number n, where it is multiplied by every number until one (ex. 7. 7*6*5*4*3*2*1), then the number in the result is n! (n factorial). So we get that 7*6*5*4*3*2*1 is 7! is 7 factorial. So 5040 is 7! </em>)
He held his breath 12 minutes and 47 seconds, which means that he was 47 seconds over 12 minutes.
So, the question is: how many milliseconds are 47 seconds?
By definition, one second is 1000 milliseconds, so 47 seconds are 47000 milliseconds.