Identify the error in the sentence.
This book is more better than that one.

Correct option is A

Option (a) more contains an error.
Detailed explanation: “better” is already the comparative form of “good.” Using “more better” creates a double comparative, which is grammatically incorrect. The correct sentence is: “This book is better than that one.”
Grammatical rule used: Use only one comparative marker. Short adjectives typically take -er (e.g., taller), longer adjectives use more (e.g., more beautiful). Irregular forms like good → better, bad → worse never take “more/most” with their comparative/superlative.
Example:
· Incorrect: She is more taller than him.
· Correct: She is taller than him.
· Information booster / exceptions: Avoid pleonastic comparatives such as more superior, more preferable, most unique. Words like unique, perfect, complete are absolute and generally don’t take comparatives/superlatives.