Statistics: Making Combinations of just a few out of a set

1. Clifford is at his local electronics store and they are having a sale on Android phone accessories. Clifford can buy up to two different accessories for $20. He has the option to purchase a case, belt clip, headphones, USB cable, vehicle charger, or screen protector. It doesn't matter which order he buys the items. How many combinations of one or two accessories are possible?

(A) 15

(B) 16

(C) 20

(D) 21

(E) 36

2. {1, 2, 3, 4, 5}

Using the set above, how many pairs of numbers can be chosen so that their product is less than 10?