Which combination correctly contrasts cis and trans double-bond configurations in unsaturated fatty acids with respect to hydrogen placement, shape, and enzymatic handling by human metabolism?

• A. Cis: hydrogens on same side, creates a kink making chain less packable and more likely a liquid at room temp; human enzymes efficiently process cis bonds. Trans: hydrogens on opposite sides, chain remains more linear enabling tight packing and solid state at room temp; human enzymes poorly metabolize many trans configurations leading to accumulation.
• B. Cis and trans differ only in melting point but are processed identically by human enzymes and have similar three-dimensional shapes.
• C. Cis: hydrogens on the same side and forms straight chains similar to saturated fats, making them solids at room temperature; Trans: hydrogens on opposite sides and always liquids at room temperature
• D. Cis: hydrogens opposite sides, linear chain, human enzymes cannot process cis bonds; Trans: hydrogens same side, kinked chain, enzymes efficiently process trans bonds.

Answer: (A)