Correct Answer: She said, “I am happy to inform you that my paper has been published in a peer-reviewed journal.

Solution : The fourth option is the correct choice.

The steps of conversion are as follows:

• There will be no change in the reporting verb "said" because it has no object.
• The third-person pronoun "she" is changed to the first-person pronoun "I".
• "Had been published" is changed to "have been published" and "was" is changed to "am". (Past tense to the present tense)
• The third-person pronoun "them" is changed to the second-person pronoun "you".
• The words of the speaker are enclosed in the inverted commas.

Therefore, the correct answer will be: She said, “I am happy to inform you that my paper has been published in a peer-reviewed journal.