On a tree, there are some parrots and pigeons in the ratio of 7 ∶ 9. After an hour 8 parrots fly and 6 pigeons and 10 sparrows come on the tree. The ratio of parrots and pigeons now is 1 ∶ 4. Now, what is the ratio of parrots to sparrows?
1
1 ∶ 2
2
3 ∶ 5
3
4 ∶ 5
4
1 ∶ 1