Explanation: 1 because a large number of just doesn't sound right and its to long but if you use many it sounds right and isn't long.
Maybe 2 because at that point in time just sounds weird and doesn't because its most likely talking about what's happened after so you would chose then but I think its 1 but if not
I think this not just because I don't know the answer its because you said page: book and they are close to each other so dirt: grass are close to each other.
