Identify correct statements from the following:
A. Propanal and propanone are functional isomers.
B. Ethoxyethane and methoxypropane are metamers.
C. But-\( 2 \)-ene shows optical isomerism.
D. But-\( 1 \)-ene and but-\( 2 \)-ene are functional isomers.
E. Pentane and \( 2 \), \( 2 \)-dimethyl propane are chain isomers.
Choose the correct answer from the options given below:
