Define a set using the set-builder method that consists of all positive integers less than 10.4.

a) x | x ∈ ℤ, 0 < x < 10.4
b) x | x ∈ ℕ, x < 10.4
c) x | x ∈ ℕ, 0 < x < 10.4
d) x | x ∈ ℤ, x < 10.4