Hey!
So when there is a scale factor you would always multiply it with the original dimensions, even if it wasn't a fraction.
so 4 time 1/5 is 0.8
and 6 times 1/5 is 1.2
so the dimensions of the model bed is 0.8 foot by 1.2 feet
Your answer is A!
Hope this helps!
The theoretical answer for the following question provided above would be found if you study