A is your answer to the question :)
Answer: the first official
Explanation: Inaugural is a word, that marks the beginning of an institution, activity, or period of office. Here the first official Groundhog Day celebration.
A bigwig refers to a person who is an expert in a particular area of study or field. Thus, a bacterial wig will be someone who is an expert in the area of bacteriology. Such a person will probably have the highest degree that is obtainable in that field and will be an authority to reckon with when it comes to the issue of bacteria.
I think it's d or b but I'm not so sure