A)
In order to check this sentence, we need to convert the value from foot to yard.
Knowing that 1 yard is equal 3 feet, we have that:

So Debbie's affirmation is incorrect, therefore we disagree.
B)
First we need to calculate the area of the table cloth.
Converting the length to foot, we have:

Now, calculating the area (which is the product of the length and the width), we have:

If each square foot is $0.25, we just need to multiply the area by the cost of one square foot in order to find the cost of the fabric for the table cloth:

So the cost is $30.