Directions: The given sentence is divided into four parts A, B, C, and D. Choose the part that contains an error as your answer. If the sentence is error-free, mark 'No error' as your answer.

As the curious child attempted to stealthily peak through (A) the intricately adorned keyhole of the antique chest, (B) a fleeting glimpse of the mysterious treasure (C) concealed within sparked his imagination. (D)