Choose the standard defining contact clause with a stranded preposition.
The colleague, I travelled with, moved abroad.
The colleague I travelled with him moved abroad.
The colleague I travelled with moved abroad.✓الإجابة الصحيحة
The colleague with I travelled moved abroad.
الشرح
In the colleague I travelled with, I is the subject and the omitted relative element is the object of with, so the construction is standard. The version ending with him is the closest distractor because him duplicates the colleague's role inside the clause.