Answer:
A. 20 A.
Explanation:
The National Electrical Code (NEC) Table 310-16 states that unless there is another specific provision in this code, the overcurrent protection in relation to the conductor types that has an obelisk( ) mark shall not be greater than 15 amps for No. 14, 20 amps for No. 12, and 30 amps for No. 10 copper; or, in relation to aluminum and copper clad aluminum, it shall not be greater than 15 amps for No. 12 and 25 amps for No. 10 after factors for ambient temperature and number of conductors have been adjusted as necessary.
Therefore, a type TW cable containing two No. 12 copper conductors can not have more than 20 A (i.e. 20 amps) overcurrent protection.
