If the thickness of thinnest outside plate is 10 mm, then the maximum pitch of rivets in tension will be taken as

The correct answer is A. 120 mm.

The maximum pitch of rivets in tension is given by the following formula:

$p = \frac{t}{2} + 3d$

where:

• $p$ is the maximum pitch of rivets in tension,
• $t$ is the thickness of the thinnest outside plate, and
• $d$ is the diameter of the rivet.

In this case, $t = 10$ mm and $d = 10$ mm. Substituting these values into the formula, we get:

$p = \frac{10}{2} + 3 \times 10 = 120$ mm

Therefore, the maximum pitch of rivets in tension is 120 mm.

Option B is incorrect because it is greater than the maximum pitch of rivets in tension. Option C is incorrect because it is less than the minimum pitch of rivets in tension. Option D is incorrect because it is greater than the maximum pitch of rivets in tension.