Option 4 : ϕ

**Concept:**

**(A ⋂ B) **are the elements present in both the sets (A and B)

**Calculation:**

Here, A = {x: x is a natural number and 1 < x ≤ 4},

A = {2, 3, 4}

B = {x: x is a natural number and 4 < x ≤ 7}

B = {5, 6, 7}

Here, not a single element is common in both sets.

So, (A ∩ B) = ϕ

Hence, option (4) is correct.