If you ... your work, let's play volleyball with them in the garden

1. If you _________ your work, let's play volleyball with them in the garden.
A. finish B. are finishing C. have finished D. will finish
2. Nam and Manh have played badminton for two hours, but _______ of them are tired.
A. none B. both C. neither D. all
Mọi người giải thích lý do chọn giùm mình nha