Answer:
[tex]\boxed{A)\ a_n=a_{n-1}+3}[/tex]
Step-by-step explanation:
[tex]a_1=-2\\a_2=1\\a_3=4\\a_4=7\\a_5=10\\\\a_2-a_1=1-(-2)=1+2=3\\a_3-a_2=4-1=3\\a_4-a_3=7-4=3\\a_5-a_4=10-7=3\\\\\text{common difference d = 3}\\\\\left\{\begin{array}{ccc}a_1=-2\\a_n=a_{n-1}+3\end{array}\right[/tex]