When the president approves a bill but also explains his plans to enforce the new law, is issued.

an executive order
a line-item veto
a signing statement
a pocket veto

In my opinion, the answer is probably the third one because it can't be the second since the president did not veto a bill while it cannot be the last one either because he did not veto the bill, so it is between the first and third. It really can't be the first one because it is not an executive order. The president is only stating his intentions so the answer is most likely the third one.