English grammar — Spot the error (choose the segment that contains a grammatical error; choose ‘‘No error.’’ if the sentence is correct). Sentence: Don't go by his appearance; he is capable at doing any work without any hesitation.

Introduction / Context:
This question checks the correct preposition after “capable.” Some adjectives require fixed prepositions, and “capable” is one of them.

Given Data / Assumptions:

• The adjective is “capable.”
• The structure used is “capable at doing …,” which is suspect.
• The intended meaning is possession of ability or competence.

Concept / Approach:
The fixed preposition with “capable” is “of,” followed by a gerund or noun: “capable of doing something.” “Capable at” is incorrect in standard English.

Step-by-Step Solution:

Verification / Alternative check:
Corrected sentence: “Don’t go by his appearance; he is capable of doing any work without any hesitation.”

Why Other Options Are Wrong:

• A: “Don’t go by his appearance;” is idiomatic and correctly punctuated with a semicolon.
• C/D: Grammatically sound.

Common Pitfalls:
Confusing “capable of” with “good at.” We say “good at doing X” but “capable of doing X.”

Final Answer:
he is capable at