vertical → chirality as it looks
horizontal → flipped
Stereochemistry in biological molecules is often denoted by the D- and L- convention, instead of the R- and S- configurations determined by the Cahn- Ingold- Prelog methodology Historically, the glyceraldehyde enantiomer that rotated plane polarized light clockwise was arbitrarily designated as "D" and the other enantiomer was designated as the "L" configuration.
The D-glyceraldehyde Fischer projection is shown below. Identify which of the following structures are equivalent to the D-configuration.
There should be 3 correct choices