The correct answer is: D. Depends upon the magnitude of R, Land C.
The magnitude of current at resonance in an R-L-C circuit depends on the magnitude of R, L, and C. At resonance, the inductive reactance and capacitive reactance cancel each other out, leaving only the resistance to oppose the current. This means that the current at resonance is maximum and is equal to \$\frac{V}{R}\$, where V is the applied voltage.
The inductive reactance is given by \$X_L = 2\pi f L\$, where f is the frequency and L is the inductance. The capacitive reactance is given by \$X_C = \frac{1}{2\pi f C}\$. At resonance, \$X_L = X_C\$, so \$2\pi f L = \frac{1}{2\pi f C}\$. This gives \$f = \frac{1}{2\pi \sqrt{LC}}\$, which is the resonant frequency.
The current at resonance is given by \$I = \frac{V}{R}\$. This means that the current at resonance is maximum and is equal to the applied voltage divided by the resistance.
The magnitude of the current at resonance is affected by the magnitude of R, L, and C. If R is large, the current at resonance will be small. If L is large, the current at resonance will be large. If C is large, the current at resonance will be small.