Unsaturated Fatty Acids Cause a Membrane to Be Fluid at Lower

Unsaturated fatty acids cause a membrane to be fluid at lower temperatures. What is a reasonable explanation for this?

A) Unsaturated fatty acids permit more water into the interior of the membrane.
B) The double bonds form a kink in the fatty acid tail, forcing adjacent lipids to be spaced farther apart.
C) The double bonds in the unsaturated fatty acids block interaction among the hydrophilic head groups of the lipids.
D) Unsaturated fatty acids have a higher cholesterol content.