Under 46 CFR §11.319, a seafarer seeking an STCW endorsement as OICNW of vessels less than 500 GT must provide evidence of bridge watchkeeping duties performed under supervision for a minimum of how long?

Why B is correct

46 CFR §11.319(a)(2) requires evidence of bridge watchkeeping duties performed under the supervision of an officer holding the STCW endorsement as master, chief mate, or OICNW for not less than 6 months. Service as boatswain, able seaman, or quartermaster with the appropriate rating endorsement may be accepted on a two-for-one basis to a maximum of 3 months credit.