Match them-

a (a-b) is a rational number 1) distributive property
b) a+0=0+a=a 2) associative property
c) a*(b+c)=a*b+a*c 3) closure property
d) a*b=b*a 4) commutative property
e) a+(b+c)=(a+b)+c 5) additive identity

I believe somewhere in the question says a and b are rational numbers.

What are your thoughts?

If you have no idea, review your notes on the terms on the right-hand side.