This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: If a problem X is in C and hard for C, then X is said to be complete for C. This means that X is the hardest problem in C. (Since many problems could be equally hard, one might say that X is one of the hardest problems in C.) Thus the class of NP-complete problems contains the most difficult problems in NP, in the sense that they are the ones most likely not to be in P. Because the problem P = NP is not solved, being able to reduce a known NP-complete problem, 2, to another problem, 1, would indicate that there is no known polynomial-time solution for 1. This is because a polynomial-time solution to 1 would yield a polynomial-time solution to 2. Similarly, because all NP problems can be reduced to the set, finding an NP-complete problem that can be solved in polynomial time would mean that P = NP. Question: If P = NP is unsolved, and reduction is applied to a known NP-complete problem vis a vis 2 to 1, what conclusion can be drawn for 1?
no known polynomial-time solution