Final answer:
The question on which structure has the s configuration requires visual interpretation or description of the molecular structures labeled A to D. The smallest atomic radius among the given options is for 2s², reflecting the general trend of atomic radius decreasing across a period.
Step-by-step explanation:
The correct answer to the original question—which structure has the s configuration—cannot be provided without the depictions or descriptions of the structures labeled A, B, C, and D. If the structures were provided, one would determine the s configuration by using Cahn-Ingold-Prelog priority rules to assign priorities to the substituents attached to the chiral center and then visualize or use the right-hand rule to determine the configuration.
To address the reference question about atomic radius—among options (a) 2s², (b) 4s² 4p³, (c) 2s² 2p⁴, and (d) 4s², the smallest atomic radius would belong to option (a) 2s², as atomic radius generally decreases across a period due to increased nuclear charge pulling electrons closer to the nucleus.