The right answer is (b) December 24, 1979. Soviet Military invaded Afghanistan on the night of December 24, 1979, deploying about 30,000 soldiers putting 0verthrow the government of Hafizullah Amin. The Soviets wanted to support a new friendly state led by Babrak Karmal; however, the mujahedin movement with American support developed and the fierce war that lasted almost nine years and claimed hundreds of thousands of lives started.