The correct answer is A: Capacitive (driven element electrically shorter than 1/2 wavelength). To use a beta or hairpin matching system, the Yagi driven element feed point impedance must be capacitive (driven element electrically shorter than 1/2 wavelength). The beta match works with capacitive reactance. The beta (hairpin) match is designed to work with a capacitively reactive feed point. This means the driven element must be slightly shorter than resonance (electrically shorter than 1/2 wavelength), making it capacitive. The hairpin (U-shaped conductor) provides inductive reactance that cancels the capacitive reactance, creating a match. If the element were longer (inductive) or at resonance (resistive), the beta match wouldn't work properly. The capacitive feed point is a requirement for beta/hairpin matching.