When you finish a problem, you should confirm that it makes sense and explain it if it does. suppose you are grading a question in which students are asked to calculate the lifetime of the sun. a student has submitted an answer of "10^−10 seconds." which of the following would be the best response to give this student when you grade this question? (a) incorrect. your answer does not make sense, because it does not have appropriate units. (b) correct. however, you should have included a sentence explaining your answer. (c) incorrect. you must have used the wrong sign for the exponent, since the lifetime of the sun is 10^10seconds, not 10^−10seconds. (d) incorrect. you are close, but i think you meant "years" rather than "seconds. (e) incorrect. your answer does not make sense, because the time is way too short.