How can I generate "what", "why" and "who" types of questions from question templates?

I was wondering if in any way it is possible to generate $$n$$ questions based on gap-fill-in type questions.

For example, the following template

______ is a process in which plants generate energy.

could lead to the generation of the following specific question

What is the process in which plants generate energy called?

If so, how can I achieve this?

I am familiar with and used natural language processing techniques, and have no problem with implementing an algorithm for this, but I do not know where to start with this.