Concept:The word “better” is a comparative adjective, so it must be followed by “than” to compare two persons.Explanation:The sentence compares Kofi’s ability in physics with the speaker’s ability.After a comparative form like “better”, the correct connector is “than”, not “as”.The verb in the second clause should match the first clause: “is better” refers to ability, so the correct expression is “I am”, not “I do”.Therefore, the correct completion is “than I am”.Answer:B. than I am