下列程序段运行后,其运行结果是()。
Dim a(3) As Integer, b(3) As Integer
For k = 0 To 3
a(k) = k*k +k
b(k) = a(k)-k
Next k
Print a(2) + b(1)

A. 5
B. 6
C. 7
D. 8