Answer:
A). When training a dog, the trainer must remember two things: the dog does not comprehend the trainer's language, and the dog cannot read the trainer's mind.
Step-by-step explanation:
Colon(:) is illustrated as the punctuation mark that is employed to reflect a separation or introduce a list or explanation in the sentence.
As per the question, the revision that best reflects the correct use of the colon would be option A as here the colon(:) is employed as a precursor to show a list of items that explains the previous sentence and describes that 'the trainer must remember two things' which are 'the dog does not comprehend the trainer's language' and 'the dog cannot read the trainer's mind'. Therefore, option A is the correct answer.