In the following question, a sentence has been given in Direct/Indirect speech. Out of the four alternatives suggested, select the one which best expresses the same sentence in Indirect/Direct speech. I said to my friend, "Be careful, my dog may bite you."

• I warned my friend to have been careful and that my dog might be biting him.
• I warned my friend to be careful and that my dog might bite him.
• I warn my friend to be careful and that my dog may bite him.
• I warned my friend for being careful and that my dog might be biting him.