Okay, let’s try to save the question:
Baby blankets are rectangular with length to width ratio approximating the golden mean (1+sqrt(5))/2 ). Since A is infeasible, and the length to width ratios needed for a perimeter 15 or perimeter 21 unit blanket are further from the golden mean that that needed for a perimeter 14 blanket, the answer is B.
(Having length to width ratio approximating the golden mean *is* a property baby blankets typically exhibit, while having exact integer length and width in “units”, which should be empirically on the order of a foot is not.)
Has anyone considered how much you need if you cut the border on the bias?