Answer:
D.)
Step-by-step explanation:
I'd say
D. Investigations; gathering evidence, collecting clues, and interviewing witness
because the first part is a sentence investigations is the ending of the sentence and then they start naming things. but they didn't put a period at the end meaning that it was the end of the sentence so then they used a semi-colleen which is the ; symbol. To separate it but not to end their sentence.
(I hope this makes some type of sense, if I'm wrong i'm sorry)