What’s the most reasonable way to get the opinions of experts on any writing topic?

What’s the most reasonable way to get the opinions of experts on any writing topic?
A. Do research at a library
B. Contact them via email
C. Call them and set up interviews
D. Contact their publishers

Ans:
Do research at a library is the most reasonable way to get the opinions of experts on any writing topic.

What’s the most reasonable way to get the opinions of experts on any writing topic?