The boys and their pets ……………….…………. I saw were cute.
a. that b. which c. who d. when

that is the correct answer
اذا سبق ضمير الوصل عاقل وغير عاقل فان:
who = that which = that
the boys (who) and their pets ( which) .......that

that is the correct answer
اذا سبق ضمير الوصل عاقل وغير عاقل فان:
who = that which = that
the boys (who) and their pets ( which) .......that

Thanks a lot , Master Mahrous

that
لانه بيقصد العاقل وغير العاقل مع بعض

that / works for both

that للعاقل والغير عاقل في نفس الجملة

that is right

That is the correct answer as you can use it in the place of who or which

اذا سبق ضمير عاقب وغير عاقل نستخدم that