Explanation

(c)
The total number of subsets of given set is $2^{9} = 512$
Case I When selecting only one even number {2, 4, 6, 8}
Number of ways$= \ ^{4}C_{1} = 4$
Case II When selecting only two even numbers$= \ ^{4}C_{2} = 6$
Case III When selecting only three even numbers$= \ ^{4}C_{3} = 4$
Case IV When selecting only four even numbers $= \ ^{4}C_{4} = 1$
$\therefore$ Required number of ways
$= 512 - (4 + 6 + 4 + 1) - 1 = 496$
[here, we subtract 1 for due to the null set]