How Does the Presence of a Double Bond Alter the Firmness

How does the presence of a double bond alter the firmness of fatty acid molecules?

A) ​D ouble bonds bend the molecule, which leads to an increase in the stacking of molecules.
B) ​D ouble bonds straighten the molecule, which leads to an increase in the stacking of molecules.
C) ​D ouble bonds bend the molecule, which leads to a decrease in the stacking of molecules.
D) ​D ouble bonds straighten the molecule, which leads to a decrease in the stacking of molecules.