Concept:
To determine the exact value of:
\[
(m-n)^2
\]
we need the exact difference between \(m\) and \(n\).
Step 1: Checking Statement (I).
Given:
\[
m,n \text{ are prime numbers}
\]
Possible cases:
\[
m=3,\; n=5
\]
\[
(m-n)^2=(3-5)^2=4
\]
Another case:
\[
m=7,\; n=13
\]
\[
(m-n)^2=(7-13)^2=36
\]
Different values are possible.
So, Statement (I) alone is not sufficient.
Step 2: Checking Statement (II).
Given:
\[
30 \leq m,n \leq 40
\]
Possible distinct integer pairs:
\[
m=31,\; n=32
\]
\[
(m-n)^2=1
\]
Another case:
\[
m=35,\; n=40
\]
\[
(m-n)^2=25
\]
Different values are possible.
So, Statement (II) alone is not sufficient.
Step 3: Checking both statements together.
Prime numbers between \(30\) and \(40\) are:
\[
31,\; 37
\]
Since \(m,n\) are distinct prime numbers in this range, the only possible values are:
\[
m=31,\; n=37
\]
or
\[
m=37,\; n=31
\]
Thus:
\[
m-n=\pm 6
\]
So:
\[
(m-n)^2=36
\]
This gives a unique value.
Hence, both statements together are sufficient.