Answer:
A). to make the text more engaging by putting a face with Harrison’s name.
Step-by-step explanation:
The addition of a visual aid always makes the idea more fascinating and easy to understand for the readers. As per the question, the key reason behind adding the painting of John Harrison painted by Tassaert is to 'make the text more appealing as it helps offer a face to Harrison's name.' It allows the readers to understand the idea more effectively and relate to the chronometer made by him better. Thus, option A is the correct answer.