we have four options here, using the elimination technique to approach this question:
First option "Accommodating" is discarded as it is not one of the conflict resolution techniques.
Second option "Compromising", I will discard it for the same reason outlined by Yasir. this is a software selection decision, and the decision can't be compromised.
Third option "Collaborating", I think normally this would be the best option. but if you recheck the question you will find the sentence "They refuse to listen to each other" which implies that collaboration technique was being tried and wasn't effective.
Forth option "Forcing", this is the last option and the correct one. forcing is the last resort since collaboration didn't work already.