Final answer:
A quarter note receives one beat in 2/4, 3/4, and 4/4 time signatures, as the '4' in the time signature indicates the quarter note is the beat unit.
Step-by-step explanation:
The number of beats a quarter note receives depends on the time signature. In a 2/4 time signature, a quarter note gets one beat because the bottom number (4) indicates that the quarter note is the beat unit, and the top number (2) tells us there are two beats per measure.
The same logic applies to a 3/4 time signature and a 4/4 time signature; in both cases, the quarter note also receives one beat per note, with three beats per measure in 3/4 time and four beats per measure in 4/4 time.