Question

What are four types of bias ?

Answer 1

There are different types of bias
1. The four types of bias are:

Propaganda
Marketing
Class
Conversely

Ethnocentrism

But because it is English I believe these are the types of bias that you're referring to:
Response Bias
Voluntary Response Bias
Nonresponse
Undercoverage

Answer 2

Undercoverage,Nonresponse,Voluntary Response Bias, Response Bias