Choose the correct exclamatory form of the sentence from the options given below:

This is an excellent piece of work.

What an excellent piece of work!

The correct answer is Option (2) → What an excellent piece of work!

Exclamatory sentences that begin with "What" or "How" are used to express strong feelings or admiration.

The standard structure for transforming an adjective + noun phrase into an exclamation using "What" is:

In this case: $$\mathbf{What}+\mathbf{an}+\mathbf{excellent}+\mathbf{piece}\mathbf{of}\mathbf{work}+!$$