Enantiomers are non-superimposable mirror images of each other. This means that no matter how you rotate or flip one enantiomer, it will not perfectly align with its mirror image. Each enantiomer has a chiral center, or a carbon atom with four different substituents attached to it, leading to two different spatial arrangements that cannot be superimposed onto each other. Therefore, Option B, which states that "Enantiomers are superimposable mirror images of each other," is NOT a true statement about enantiomers. As for the other options: Option A is true: Enantiomers have the same physical properties, such as refractive index, boiling point, and melting point, in an achiral environment. Option C is mostly true: Enantiomers have the same chemical properties in achiral environments or with achiral reagents, but they can behave differently in chiral environments or with chiral reagents, including biological systems. Option D is true: Enantiomers have equal but opposite optical rotation; one enantiomer will rotate plane-polarized light to the right (dextrorotatory, or + ) and the other to the left (levorotatory, or - ) by the same magnitude, but in opposite directions.