The correct option is
C Who's this painting by
Option A: The tourist's question, 'Who is this painting by?' is answered by the guide's answer, 'This is the by ...., Rembrandt'. Hence, option A is correct.
Option B: The answer to the question, 'Do you like modern art?' can begin either with, 'Yes, I like it/ love it'; Or 'No, I do not like it'.
Option C: The answer to the question, 'Can I take photographs?' can begin either with, 'Yes, you can '; Or 'No, you cannot'.
Option D: The answer to the question, 'Who is in the painting?' can be, 'It is .......... (name of the person/ description of the person)'.
The questions in options B, C and D cannot be the answered by the guide's reply i.e 'This is by the famous Dutch painter and etcher, Rembrandt'. Hence, options B, C and D are incorrect.