It's believed that the role of feasts in the ice age was to
a. celebrate weddings.
b. celebrate the resolution of serious conflicts.
c. strengthen group ties.
d. mark times when food was abundant.
a. recorded law codes.
b. was used for religious texts.
c. can't be deciphered.
d. relates to stories of heroes.

It's believed that the role of feasts in the Ice Age was to "c. strengthen group ties," since this has to do with "group selection theory," which holds that individuals who are part of a social "team" have a better chance of survival. 

Feasts during the Ice age had multiple uses and benefits. They were there to celebrate resolution of serious conflicts  - B, strengthen group ties - C, mark times when food was abundant - D. However, this should be taken with great caution, it can be hard to interpret things people did in those times due to lack of information from those times. 

Assuming that this is referring to the same list of options that was posted before with this question, the best response is "unrestricted" since the Germans underwent a campaign of sinking merchant vessels.