Step 1: Linguistic Definition of a Sentence:
In grammar, a sentence is the largest independent unit of syntactic structure. It must contain a subject and a predicate, and must stand alone as a coherent unit of meaning.
Step 2: Analysis of the Options:
Option (A) defines a paragraph. Option (C) defines grammar. Option (D) only focuses on punctuation. Option (B) captures the semantic and structural essence of a sentence.
Step 3: Syntax Check:
A valid sentence must satisfy both grammatical structure (subject + verb) and semantic completeness (conveying a complete thought). Option (B) correctly captures this definition.