According to the sources, the current in an AC circuit is given by $I = V/Z$ . For a resistor, the impedance $Z = R$ is independent of frequency . For an inductor, the inductive reactance is $X_L = 2\pi f L$, meaning impedance increases with frequency and current decreases . However, for a capacitor, the capacitive reactance is $X_C = 1/(2\pi f C)$ . As the frequency $f$ increases, $X_C$ decreases. In a circuit containing only a capacitor ($Z = X_C$) or a resistor and capacitor in series ($Z = \sqrt{R^2 + X_C^2}$), the total impedance $Z$ will decrease as frequency increases, which leads to an increase in current $I$. Therefore, elements (c) and (d) are the likely constituents.