**Concept: The question tests on the area of Modern Math (Counting/Combinatorics)**

**Solution:**

The total number of ways of choosing at least 1 from n distinct objects is 2^n - 1

here n = 5

Therefore the total number of ways = 2^5 - 1 = 31

Another way of looking at this is that if we have to find the number of ways he can fail, then he can fail in 1 subject or 2 subjects or 3 subjects or 4 or 5 subjects

= 5C1 + 5C2 + 5C3 + 5C4 + 5C5

= 5 + 10 + 10 + 5 + 1

= 31

**(option d)**