Final answer:
21, 34, and 55 are pairwise relatively prime.
Step-by-step explanation:
Two numbers are relatively prime if they have no common factors other than 1. To determine if 21, 34, and 55 are pairwise relatively prime, we need to check each pair of numbers.
For 21 and 34, their greatest common divisor (GCD) is 1, which means they are relatively prime.
For 34 and 55, their GCD is also 1, so they are relatively prime.
Since all the pairs have a GCD of 1, we can conclude that A) Yes, 21, 34, and 55 are pairwise relatively prime.