Enantiomers are isomers that differ in structure at which carbon :: (A) Last Carbon, (B) First Carbon, (C) Penultimate Carbon, (D) Carbonyl Carbon
Answer is C. Enantiomers have different -H and -OH orientation around the penultimate carbon /2nd last carbon/Reference carbon. E.g-. D-and L-Glyceraldehyde. Also known as Mirror images of each other.