Exit
which pair of numbers is relatively prime?
a. 108 and 57
b. 21 and 183
c. 55 and 121
d. 60 and 151

Its not A because 108 and 57 are both divisible by 3

if you write  the numbers in prime factor form you will see the correct optiuon

for example B:-

21 = 3* 7
183 = 3 * 61       3 is common to both factors so its not B