Answer:
The correct option is 1. The area of cross section area is 48 mm².
Step-by-step explanation:
From the find it is noticed that the cross section is a rectangle with length 4 mm and width is 12 mm.
The area of a rectangle is the product of its dimensions.

Where, l is length of the rectangle and w is width of the rectangle.
The area of cross section is


Therefore the area of cross section area is 48 mm². Option 1 is correct.