The@RestResourceannotation exposes an Apex class as a RESTful web service. TheurlMappingparameter defines the endpoint's URL.
Reference:Apex REST Services
Incorrect Options:
A:@RemoteActionis used for JavaScript remoting.
C:@HttpInvocableis used for invocable methods, not REST services.
D:@AuraEnabledis for enabling methods in Aura components or LWC, not REST services.