Question

Improper or incomplete usage of citations can lead to

a. plagiarism.
b. libel.
c. copyright.
d. malfeasance.

Answer 1

plagiarism because you're technically taking someone else work without giving them credit if you dont use citations. 

Answer 2

Improper or incomplete usage of citations can lead to plagiarism.

Without proper usage of citations, teachers or whoever is looking over your work, may think because you do not hold acceptable citations, that they will think it is plagiarized. Plagiarism is taking another person's work or ideas without citing it. Citation or direct quotation could save you from plagiarism.