Prove: if a+c=b+c, then a=b. statement 1: a+c=b+c statement 2: a+c+(-c)=b+c+(-c)

Prove: if a+c=b+c, then a=b.
statement 1: a+c=b+c
statement 2: a+c+(-c)=b+c+(-c)
statement 3: a+[c+(-c)]=b+[c(-c)]
statement 4: a+0=b+0
statement 5: a=b.
what is the reason for statement 2?
a. property of opposites
b. associative property of addition
c. addition property of equality
d. identify property of addition