Answer:
B. Take defensive strike action.
Step-by-step explanation:
One of the functions of a trade union or labor union is to protect the interest of its members in a workplace. So, if a profit firm treats its workers poorly by underfunding contribution to workers pension as required under a collective agreement while paying out record bonuses to executives then attempts attempt to reduce workers pension entitlements, the union members will most likely embark on an industrial strike.
The aim of the strike is to halt daily operations of the firm until their demands are heard and an agreement is reached. The members of the union were treated unfairly by the firm by not honoring their pension funding agreement and to make matters worse the decided to try and reduce the workers pension.
If the members don't embark on the industrial strike, the firm would reduce their pension benefits. The most likely action of the union members would be to embark on a defensive strike action to protect themselves.