In an Artificial Grammar Task,participants Are Shown Strings of Letters

In an artificial grammar task,participants are shown strings of letters labelled "grammatically correct" and "grammatically incorrect." Then they are shown new strings and are asked to classify them as correct or incorrect.Participants usually are:

A) unable to do the task,unless explicitly told the grammatical rules.
B) unable to do the task,even after being told the grammatical rules.
C) quite good at the task and can articulate the grammatical rules.
D) quite good at the task but cannot articulate the grammatical rules.