(68)                     

A A student's success in an examination, therefore, helps employers and others to assess his mental or general ability.

B A student's success in an examination, however, prevent employers and others to assess his mental or general ability.

C A student's success in an examination, otherwise, helps employers and others to appreciate his mental or general ability.

D A student's success in an examination, therefore, discourages employers and others to assess his mental or general ability.