Please explain why

Consider a multi-user system where each user runs multiple threads and users usually have at least one thread that can use the processor at any time. Suppose one wanted to use a lottery scheduler on this system to achieve the following goals: 1. each user gets approximately the same amount of CPU time (divided somehow among the threads they can run); 2. to the extent practical without violating goal 1, each user's threads experience the lowest possible mean turnaround time Which mechanism (of the choices below) for allocating tickets to threads would make most sense for these goals? assign each thread tickets proportional to the approximate remaining time in its CPU burst; then, for each user, count the total number of tickets A. assigned to their threads, and divide the number of tickets assigned by 1000 times this number (so each user ends up with about 1000 tickets) B. assign each user a fixed total number of tickets to be divided among all their threads. Divide a user's tickets evenly among their threads. assign each user a fixed total number of tickets to be divided among all their threads. Divide a user's tickets among their threads such that the C. thread with the lowest remaining time in its CPU burst gets about 100 times more tickets than the user's other threads