Concept:
Relative pronouns are used to connect a clause or phrase to a noun or pronoun. When using indefinite pronouns like anything, everything, nothing, or all as an antecedent, the relative pronoun "that" is preferred over "what."
Step 1: Identify the relative pronoun error.
The sentence uses "what" after "anything." In English grammar, "what" acts as its own antecedent (it means "the thing that"). Since "anything" is already present as the object, using "what" creates a redundant structure.
Step 2: Determine the correct replacement.
The correct relative pronoun to follow "anything" is "that" (or sometimes it can be omitted entirely).
"...give him anything what he wants..."
• Correct: "...give him anything that he wants..."
Step 3: Address secondary tense issues (Optional Note).
While the primary error for competitive exams is the relative pronoun in part (B), there is also a tense inconsistency. "Promised" (Past) usually dictates "wanted" and "passed." However, in many standardized error-detection tests, the most fundamental structural error (Relative Pronoun) is prioritized.