Final answer:
The word 'semicircle' contains the Latin prefix 'semi-' which means 'half'. The prefix is combined with the stem 'circle', indicating something that is half of a circle in shape. The correct answer is option d.
Step-by-step explanation:
The word that contains a Latin prefix meaning "half" is semicircle. The prefix semi- comes from the Latin semis, which means half or partly. When we analyze the word semicircle, 'semi-' is the prefix and 'circle' is the stem. This combination of prefix and stem indicates something that is half a circle or forming a half circle.
In reviewing the other words: 'forelock' does not have a prefix related to the concept of "half"; 'prepaid' has the prefix 'pre-' which means 'before'; and 'retrace' has the prefix 're-' which means 'again' or 'back'. Therefore, these do not include a prefix meaning "half".