Answer:
The correct option is 3.
Explanation:
The area of a triangle is

Where, b is base of the triangle and h is the height of the triangle.
From the given figure it is noticed that the base of the triangle is 10 cm and the height of the triangle is 7 cm.
The triangle enlarged by a scale factor of 10. Now,


The area of new triangle is


Therefore the area of new triangle is 3500 cm². Option 3 is correct.