Answer:
a.Word-for-Word plagiarism
Step-by-step explanation:
This is word-for-word plagiarism because the student had quoted part of the work of the original source word for word and had failed to provide references(citing or bibliography). The student's version starts off with his own explanation but goes ahead to quote the original source where he writes "a theory is just a model of the universe, or a restricted part of it, and a set of rules that relate quantities in the model to observations that we make" without properly citing the author of this definition for theory. This is therefore word-for-word plagiarism as there were no references for work borrowed from and the student therefore claims the original source's definition for theory to be his own.