Concept:
Metaethics studies the meaning, nature and status of moral statements.
It asks questions like:
\[
\text{What does ``good'' mean?}
\]
\[
\text{Are moral judgements objective or subjective?}
\]
Step 1: Check Non-naturalism.
Non-naturalism is a metaethical theory.
So:
\[
A = \text{Correct}
\]
Step 2: Check Emotivism and Prescriptivism.
Emotivism says moral statements express emotions.
Prescriptivism says moral statements function as prescriptions.
Both are metaethical theories.
So:
\[
C,\ D = \text{Correct}
\]
Step 3: Check Relativism.
Relativism is also discussed in metaethics because it deals with the status and context of moral truth.
So:
\[
E = \text{Correct}
\]
Step 4: Check Utilitarianism.
Utilitarianism is a normative ethical theory, not a metaethical theory.
So:
\[
B = \text{Incorrect}
\]
Therefore, the correct set is:
\[
A,\ C,\ D,\ E
\]
Hence:
\[
\boxed{\text{(D) A, C, D and E only}}
\]