Answer:
A. Read a book about cows
Explanation:
B. Personal interviews are often opinionated and bias. Plus you can't interview the source, a cow, for the most accurate info.
C. Magazines are unprofessional, subjective, and bias.
D. Web, self-explanatory. So many sources you can't tell what's most accurate, and you're exposed to a lot of bias.
Books can have bias, but out of all the other options it is the better choice.
