I can't use your pen, ___ there is no ink in it.                   A. for    B. when   C. if    D. whether 

I can't use your pen, ___ there is no ink in it.                   A. for    B. when   C. if    D. whether 

I can't use your pen, ___ there is no ink in it.                   A. for    B. when   C. if    D. whether 

I can't use your pen, ___ there is no ink in it.                   A. for    B. when   C. if    D. whether 

I can't use your pen, ___ there is no ink in it.                   A. for    B. when   C. if    D. whether