All threads of a process share the same page table. The point of having threads is to be able to have multiple tasks operating on the same memory. Threads are supposed to be fast, so there would be a lot of overhead if the entire page table had to be copied whenever a thread was created. We also want context switching to be fast, so we want to avoid having to switch between page tables when a different thread starts to execute
So it doesn't matter how many threads a process has, there will be only one page table. Thus, Ans: 3 Page tables.
Ref: http://web.cs.ucla.edu/classes/winter12/cs111/scribe/15e/