In the following question, the sentence given with blank to be filled in with an appropriate word. Select the correct alternative out of the four and indicate it by selecting the appropriate option.
I was taken _________ by the server's rude comment about my hair.

The phrasal verb "taken aback" means to be shocked or surprised by something unexpected.
In the context of receiving a rude comment out of nowhere, "taken aback" fits perfectly.

Taken away means removed.

Taken off means removed clothing or a flight departing.

Hence, aback is the correct choice.