The teacher told him that he would have _____ if he______.         [ ]

A.  better lives, work hard              

B.  a better life, work ard

C.  better life, works hard              

D.  a better life, worked hard

若二维数组arr[1..M，1..N]的首地址为base，数组元素按列存储且每个元素占用K个存储单元，则元素arr[i，j]在该数组空间的地址为（）。

A．base+((i-1)*M+j-1)*K

B．base+((i-1)*N+j-1)*K

C．base+((j-1)*M+i-1)*K

D．base+(j-1)*N+i-1)*K