If i have three things to do this evening: study math, finish my chores, and to answer e-mails. The correct option is:C study math, finish my chores, and answer e-mails.
What is study?
The infinitive marker "to" appears before each item on the list in the original text. It is not required to repeat the infinitive marker before each item in standard English, nevertheless. Before the first item in the list, the word "to" only needs to be used once.
As a result, the sentence needs to be revised to read: study math, do chores, and respond to emails. This form is the most condensed and grammatically correct one since it eliminates the needless repeating of the infinitive marker.
Therefore the correct option is C.