Per Table 250.122, a branch circuit protected by a 60 A overcurrent device requires a copper equipment grounding conductor of at least what size?
Not quite. The answer is B: 10 AWG
Table 250.122 sizes the equipment grounding conductor from the rating of the overcurrent device protecting the circuit, not from the circuit's load or the conductor's ampacity. A 60 A device calls for a 10 AWG copper EGC. If the ungrounded conductors are increased in size for a reason such as voltage drop, 250.122(B) requires the EGC to be increased in the same proportion; and where conductors run in parallel in multiple raceways, each raceway gets its own EGC sized per the table for the circuit's overcurrent device.
Reference: NEC 2023 Table 250.122 (Equipment Grounding Conductor Sizing)
Checked against multiple published sources
An NFPA fact sheet (2020 NEC), a Mike Holt 2020 NEC text and an IAEI article all show 10 AWG copper for a 60 A device in Table 250.122. All are written against the 2020 edition; none is the code text.