The word "precedent" consists of the root "cede" meaning "go" or "yield" and the prefix "pre-" meaning "before."
A. practical - This word does not share any word part with "precedent."
B. portents - This word does not share any word part with "precedent."
C. preference - This word shares the prefix "pre-" with "precedent," both indicating "before."
Therefore, the word that shares a word part with "precedent" is C. preference.