Concept:
Interior scaping means using plants inside buildings for beauty, comfort, health and better working environment.
Step 1: Check statement A.
Interior plants do not enhance noise levels. Instead, they may help reduce noise.
\[
A \text{ is incorrect}
\]
Step 2: Check statement B.
Interior scaping does not reduce sales. Good interior scaping may improve customer attraction and business environment.
\[
B \text{ is incorrect}
\]
Step 3: Check statement C.
Indoor plants help improve indoor air quality by absorbing pollutants and increasing freshness.
\[
C \text{ is correct}
\]
Step 4: Check statement D.
A good indoor green environment improves mood and work performance.
\[
D \text{ is correct}
\]
Step 5: Check statement E.
Interior plants help reduce stress levels.
\[
E \text{ is correct}
\]
Thus, the correct statements are:
\[
C,D,E
\]
\[
\therefore \text{Correct Answer is (D)}
\]