np complete problem question

this problem is NP-complete You own a car rental business and rent cars out by the day for drivers who want to go on a roadtrip. A roadtrip may take place in multiple (possibly not consecutive) days, and it is only possible to go on a roadtrip if we rent the car for all of those days. It is not possible to rent out multiple cars on a single day. To make rentals easier, you are only worried about rentals that stretch out to at most D days in the future. The goal is to be able to make as many rentals as possible during D days. The problem: Given input: the total number of days D n rentals R1, ..., Rn and an integer k. Each Ri is a subset of (1, 2, . . rental takes place. , D) indicating the days on which that Find if it is possible to schedule at least k rentals such that if rentals Ri and Rj are scheduled, then Ri NRj = 0. Call this problem CarRental. Prove that CarRental E NP. Find a NP-complete problem to reduce from. And prove that the reduction is correct. this problem is NP-complete You own a car rental business and rent cars out by the day for drivers who want to go on a roadtrip. A roadtrip may take place in multiple (possibly not consecutive) days, and it is only possible to go on a roadtrip if we rent the car for all of those days. It is not possible to rent out multiple cars on a single day. To make rentals easier, you are only worried about rentals that stretch out to at most D days in the future. The goal is to be able to make as many rentals as possible during D days. The problem: Given input: the total number of days D n rentals R1, ..., Rn and an integer k. Each Ri is a subset of (1, 2, . . rental takes place. , D) indicating the days on which that Find if it is possible to schedule at least k rentals such that if rentals Ri and Rj are scheduled, then Ri NRj = 0. Call this problem CarRental. Prove that CarRental E NP. Find a NP-complete problem to reduce from. And prove that the reduction is correct