Answer:
Area of triangle B is 112 cm²
Option A is correct option.
Step-by-step explanation:
The dimensions of triangle B are twice the dimensions of triangle A.
Area of triangle A = 28 cm²
We need to find area of triangle B
We know that if base = b and height = h for triangle A
The area of triangle A will be: 
The dimensions for triangle B will be:

Putting in formula we get:

SO, we get 
We have Area_A = 28 cm²
Area of triangle B Area _B is:

So, Area of triangle B is 112 cm²
Option A is correct option.