Answer:
The correct option is A: "He is trying to increase his accuracy but not his precision"
Step-by-step explanation:
Accuracy of measurement is when the value of the measurement is close to the actual value of that measurement while precision is when the experiment is repeated using the same instrument but obtaining different values.
When Boyd changed the weighing balance in his experiment to a smaller one, the smaller weighing balance has better accuracy (smaller graduations) than the initially used one because the smaller weighing balance will provide a value close to the actual value of the mass of the product. If he had, however, repeated the experiment without changing the weighing balance, he would have sought to increase his precision.
From the description above, it can be said that Boyd was trying to increase his accuracy but not his precision