He always did well at school_________having to do part-time jobs every now and then.    [      ]

A. in spite of                

B. regardless of    

C. on account of            

D. in case of

分子式为C₈H₁₆O₂的有机物A，它能在酸性条件下水解生成B和C，且B在一定条件下能转化成C。则有机物A的可能结构有[ ]

A．1种

B．2种

C．3种

D．4种