Multiple choice general knowledge math & puzzles

In the group G = {0, 1, 2, 3, 4, 5} under addition module 6, a subgroup is:

  1. ( 0, 3, 5)

  2. ( 0, 4, 5)

  3. ( 0, 1, 3)

  4. ( 0, 2 ,4)

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A subgroup must contain the identity element (0) and be closed under the operation. In addition modulo 6, {0, 2, 4} is closed because 2+2=4, 4+2=0, and 4+4=2. The other sets are not closed; for example, in {0, 3, 5}, 3+5=2, which is not in the set.