Which of the following compounds can in principle be isolated in optically active form at room temperature? Select all valid choices.

Question

a. trans-1,3-dimethylcyclohexane
b. cis-1-ethyl-3-methylcyclohexane
c. 1,1-dimethylcyclohexane
d. cis-1,4-dimethylcyclohexane

Answer 1

I would go with answer choice B. In order for something to be optically active, the substance should not have a plane of symmetry. Only answer choice B doesn't have a plane of symmetry.

Answer 2

The answer was A and B

Answer 3

Can confirm, it's definitely A and B:
trans-1,3-dimethylcyclohexane
and
cis-1-ethyl-3-methylcyclohexane