Answer:
C. :
Step-by-step explanation:
A colon is the best punctuation mark to use in the blank. A colon can be used before a quote when there is a complete sentence before the quote. Otherwise, a comma is an appropriate to separate a quote from the rest of the sentence. In this case, "These were his words" is a complete sentence. Therefore, a colon, rather than a comma,is the appropriate punctuation.