Which sequence is graphed below?
a. an = n – 2
b. an = n – 1
c. an = n + 1
d. an = n + 2

Looking at the chart you see that the initial term is -1 and each successive term is 1 more than the previous one.  The rule for nth term of an arithmetic sequence is:

a(n)=a+d(n-1), a(n)=nth term, a=initial term, d=common  difference, n=term number.

In this case a=-1 and d=1 so

a(n)=-1+1(n-1)

a(n)=-1+n-1

a(n)=n-2

So the correct answer is A)