According to the 'Probable Answers' section, 'Brave' is identified as an Adjective in the sentence 'Hasib is a brave boy'.
Class 6 › English Grammar and Composition › Chapter 11: Answer Key, Sample Question and Guidelines › Topic: Grammar Section (Parts of Speech, Gap Filling, Sentence Making, Verb Forms, Sentence Transformation, Punctuation)
Aligned to the NCTB national curriculum.