Which one of the following three sets is a reduced residue system modulo 8?

A: {1,2,3,5,7}

B: {1,3,5,7}

C: {2,3,5,7}

D: {1,3,5,8}

option B

Step-by-step explanation:

The reduced residue system modulo is the set for a number in which greatest common divisor is 1 for the set of the number from the set and the number belonging to residue system modulo

for the given problem,

g. c. d (n, 8) = 1,

here, n is the number from the set

thus, for the option B {1, 3, 5, 7}

for, n = 1

g. c. d (1,8) = 1,

for, n = 3

g. c. d (3,8) = 1,

for, n = 5

g. c. d (5,8) = 1,

for, n = 7

g. c. d (7,8) = 1,

hence, for every 'n' belonging to the set given in the option B satisfies the condition

hence, option B is correct