Correct Answer: The professor said to me, “You cannot rescue yourself from this bait.”

Solution : The fourth option is the correct choice.

The original sentence is a reported speech, where the professor is conveying information to the speaker. Direct speech is a form of speech or writing where the actual words spoken by a person are quoted within inverted commas and attributed to the speaker.

The steps of conversion are as follows:

• The reporting verb "told" is changed to "said".
• The first-person pronouns "I" and "myself" are changed to the second-person pronouns "you" and "yourself", respectively.
• The modal "could" is changed to its simple present form, "can".
• The determiner "that" is changed to "this".
• The words of the speaker are enclosed in the inverted commas.

Therefore, the correct answer is: The professor said to me, “You cannot rescue yourself from this bait."