In which sentence does the underlined noun clause function as a direct object?

whoever works as a lifeguard needs special training.

experts say that one of the best times to put on sunscreen is when you exit the water.

we like to set up our blanket in whatever place gets some shade

you must pack whatever you need for the beach.

Seems that you forget to indicate if which one is underlined so I'll just answer based on the sentences you have given.

Based on the sentences, I can say that the noun clause that functions as a direct object would be the last sentence. You see, the noun clause here is "whatever you need for the beach", and this is the direct object receiving the action from the verb "pack". Hope this helps.