Step 1: Understand the context of the sentence.
"Putting on" is the correct phrase when referring to wearing something, such as a hat.
Step 2: Evaluate the options.
% Option
(1) getting on: Incorrect phrase.
% Option
(2) putting on: Correct phrase for wearing an item.
% Option
(3) taking on: Incorrect; refers to accepting a task, not wearing.
% Option
(4) no improvement: Not needed, as the correct phrase is "putting on."