Introduction:
A strong base is a substance that can easily accept a proton (H+) and has a high affinity for hydrogen ions. It is capable of abstracting a hydrogen atom from a molecule, resulting in the formation of a new compound.

Explanation:
A strong base can abstract a hydrogen from a ketone. Let's understand why this is the correct answer.

What is a ketone?
A ketone is a type of organic compound that contains a carbonyl group (C=O) bonded to two other carbon atoms. It is represented by the general formula R-C(=O)-R', where R and R' can be alkyl or aryl groups.

Why can a strong base abstract a hydrogen from a ketone?
1. Acid-Base Reaction:
When a strong base reacts with a ketone, it acts as a Lewis base and donates a pair of electrons to the carbonyl carbon atom in the ketone. This leads to the formation of a negatively charged intermediate known as an enolate ion.

2. Formation of Enolate Ion:
The enolate ion has a negative charge on the carbon atom, which can be stabilized by resonance. This stability is enhanced when there are electron-withdrawing groups present on the carbonyl carbon.

3. Abstracting Hydrogen:
Since the enolate ion is negatively charged, it can easily abstract a hydrogen atom from a neighboring molecule. This hydrogen can come from a variety of sources, such as water, alcohols, or other organic compounds.

4. Resulting Product:
The abstracted hydrogen forms a new bond with the enolate ion, resulting in the formation of a new compound. This process is known as an enolate alkylation or enolate condensation reaction.

Conclusion:
In summary, a strong base can abstract a hydrogen atom from a ketone due to the ability of the ketone to form an enolate ion. This reaction is important in organic chemistry as it allows for the formation of new carbon-carbon bonds and the synthesis of various organic compounds.