Which graph shows a proportional relationship? There's more than one answer

graph A
graph B
graph C
graph D​

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the answer is:

the correct option is the option b.

to calculate the surface area of the right cylinder, we need to use the following formula:

from the picture we know that:

so, substituting and calculting we have:

hence, we have that the correct option is the option b.

have a nice day!