In a small-signal equivalent circuit of a diode, what is the primary parameter that determines the small-signal resistance of the diode?

Correct option is B

​$$\text{In small-signal analysis, the diode is modeled using its \textbf{dynamic (small-signal) resistance}, given by:} \\[6pt]r_d = \frac{V_T}{I_D} \\[8pt]\textbf{Where:} \\[4pt]\bullet \ V_T = \text{ thermal voltage } (\approx 26 \, \text{mV at room temperature}) \\[2pt]\bullet \ I_D = \text{ DC bias current through the diode}$$​​