THE CORRECT ANSWER IS B. THE CONCLUSION OF THE ARGUMENT IS THAT MI...

13. The correct answer is B.

The conclusion of the argument is that Michelangelo must have

completed the painting between 1507 and 1509. The basis for that

claim is that the painting depicts a coin that did not exist before

1507 and that it contains a pigment that Michelangelo ceased using

in 1509. We are asked to find an assumption that completes the

logic of this argument.

Choice A is incorrect. We do not need to assume that no stocks of

the pigment existed after 1509. The argument is concerned only

with the year in which Michelangelo stopped using the pigment.

Choice B is correct. In order to conclude that the painting must have

been completed before 1509 on the basis of the pigment, we must

assume that he did not begin the painting before 1509 using the old

pigment and complete the painting after 1509 with the new

pigment.

Choice C is incorrect. The fact that the general public knew of the

coin in 1507 is irrelevant to the conclusion.

Choice D is incorrect. The fact that the panel cannot be tested for

age does not relate to either the coin or the pigment, the two bases

for the conclusion.

Choice E is incorrect. Whether Michelangelo's painting style changed

during this period does not relate to either the coin or the pigment.