Hey there!
Let's find their areas first. Rectangle area is defined as length times width, so we have:
A- 10 * 4 = 40 units squared
B- 4 * 2 = 8 units squared
Let's try all of our answers:
A) If A had twice the area, it's area would be 8. No
B) This is true, as 40 is 8 times 5, so rectangle A has 5 times as much area.
Your answer is B.
Hope this helps!