The correct answer is C. Reassurance.

The image depicts piezogenic papules, a benign entity associated with fatty connective tissue protrusion (most commonly) of the heel. Plain film of the foot will not reveal anything. Magnetic resonance imaging of the foot may provide additional detail particularly if the foot were under pressure – revealing areas of slight protrusion of fatty connective tissue – but imaging is not necessary to make this diagnosis.

Punch biopsy and tissue culture are unnecessary and will do more harm than good.

References:Turkmani MG1. Piezogenic pedal papules treated successfully with deoxycholic acid injection. JAAD Case Rep. 2018 Jun 13;4(6):582-583. doi: 10.1016/j.jdcr.2018.03.027. eCollection 2018 Jul.