Answer: d. Core rigidity
Step-by-step explanation:
Core rigidity refers to the tendency of companies that are successful in the market to become comfortable in their position because they feel their core mode of operations is fine. They will therefore abandon or significantly reduce improvement efforts which usually ends badly because competitors will keep improving.
Those in favor of the change are struggling against a Core Rigidity mindset in the people opposed to the move because those ones want to remain in their current strengths instead of trying to improve operations.