Two A.P.'s have the same common difference.

Here, we are given two A.P.’s with same common difference. Let us take the common difference as d.

Given,

First term of first A.P. (a) = 8

First term of second A.P. (a’) = 3

We need to find the difference between their 30th terms.

So, let us first find the 30th term of first A.P.

$a_{30}=a+(30-1) d$

$=3+29 d$ $\ldots(1)$

Similarly, we find the 30th term of second A.P.

$a_{30}^{\prime}=a^{\prime}+(30-1) d$

$=3+29 d$ ........(2)

Now, the difference between the $30^{\text {th }}$ terms is,

$a_{30}-a_{30}^{\prime}=(8+29 d)-(3+29 d)$

$=8+29 d-3-29 d$

$=8-3$

$=5$

Therefore, $a_{30}-a_{30}^{\prime}=5$

Hence, the correct option is (d).