Answer: A. 7pi>21.
7 times pi is 21.9911486, which is more than 21, which would mean this equation is correct.
n +4 is 7.14159265, which means that the less than sign should be facing the opposite way, this one is incorrect.
3 times pi minus 1 is 5.14159265, which is less than nine, meaning the greater than sign should be facing the opposite way, this equation is incorrect.
Lastly 12/4pi is 0.954929659, which is less than 1, the sign once again is facing the wrong way, this problem is incorrect.
This means our correct answer is A. 7pi>21.
HOPE THIS HELPS & GOOD LUCK