According to the dean, the goal of gainfully employment is apparently to protect students from getting into unsustainable debt.

Explanation

The sentence has an error in option (b). Here's the corrected version:"According to the dean, the goal of gainful employment is apparently to protect students from getting into unsustainable debt."The error is in the use of "gainfully." The correct term here is "gainful." "Gainful employment" is a phrase commonly used to refer to employment that provides a sufficient income to meet one's needs. The mission is to secure parallelism by using "gainful employment" instead of "gainfully employment" in reference to "unsustainable debt" .So, the corrected sentence is: "According to the dean, the goal of gainful employment is apparently to protect students from getting into unsustainable debt."