Which of the following molecules has the $S$ configuration at its only stereocenter?

• A. A molecule with the structure: $CHBrClF$ where the priorities are $Br$ > $Cl$ > $F$ > $H$ and the arrangement is such that the sequence $Br$ → $F$ → $Cl$ is clockwise with $H$ in the back.
• B. A molecule with the structure: $CHBrClF$ where the priorities are $Br$ > $Cl$ > $F$ > $H$ and the arrangement is such that the sequence $Cl$ → $Br$ → $F$ is clockwise with $H$ in the back.
• C. A molecule with the structure: $CHBrClF$ where the priorities are $Br$ > $Cl$ > $F$ > $H$ and the arrangement is such that the sequence $Br$ → $Cl$ → $F$ is counterclockwise with $H$ in the back.
• D. A molecule with the structure: $CHBrClF$ where the priorities are $Br$ > $Cl$ > $F$ > $H$ and the arrangement is such that the sequence $Br$ → $Cl$ → $F$ is clockwise with $H$ in the back.

Answer: (C)

Verified step by step guidance

1. Identify the priorities of the substituents attached to the stereocenter using the Cahn-Ingold-Prelog (CIP) priority rules. In this problem, the priorities are given as Br > Cl > F > H.
2. Orient the molecule so that the lowest priority group (H) is pointing away from you (in the back). This is crucial because the configuration assignment depends on this orientation.
3. Trace the path from the highest priority substituent (1) to the second (2), then to the third (3). Observe the direction of this sequence: if it is clockwise, the configuration is R; if counterclockwise, the configuration is S.
4. If the lowest priority group is in the back and the sequence 1 → 2 → 3 is counterclockwise, then the stereocenter has the S configuration. If the sequence is clockwise, the configuration is R.
5. Apply these rules to each given molecule's arrangement to determine which one has the S configuration at its stereocenter.