How can you hold "one of each" if you have four cards and no trump?21) Your partner picked up the Ace of hearts. First seat leads the 10 of clubs. You take the trick with the only ace in your hand. Third seat follows suit and your partner throws off the 10 of spades. You hold no trump.
Assuming you hold one of each, what suit do you lead back?
Also, the wording is different in the explanation at https://ohioeuchre.com/E_Euchre_Quiz_Results_What_Ive_Learned.php:
You still have four cards, don't you?Assuming you hold one of each of the other three suits, what suit do you lead back?

FWIW, I agree with the answer.