Which of the following sentences is a definition?

A、A racist can be defined as a prejudiced person who discriminates because of another individuals outer appearance or race. ;
B、Racism can all start as a child being raised with negative thoughts, or can be brought upon by personal reasons.;
C、For example, growing up in a racist family will give adolescent awful thoughts about a race without even experiencing how they really feel first hand.;
D、A different example of how one might unfortunately choose to be racist would be if a person visits a country, and a negative event took place.