The question is essentially asking us to find the odd factors of 10!
On prime factorising, you get the values as 2^8 * 3^4 * 5^2 * 7^1 and since we are calculating only the odd factors, we can drop 2^8 and just calculate (4 + 1)(2 + 1)(1 + 1) which gives you 30 (option A, as what is circled in the screenshot).
However, the question does not mention anything about the factors being only positive. Hence, shouldn’t we multiply it by 2, to account even for the negative factors resulting in the answer being 60(option B)?
