A.I. Explanation:

Option 1: "Introduction of electric buses"

Explanation: This option is incorrect because the text states that electric buses aim to reduce carbon emissions and provide a quieter ride, but it does not mention anything about making cycling safer or more appealing. Therefore, it does not relate to the specific initiative aimed at cycling.

Option 2: "Expansion of the city's cycle lanes"

Explanation: This option is correct as the text explicitly states that London has expanded its cycle lanes, which directly addresses the initiative aimed at making cycling safer and more appealing for residents and visitors. The expansion of cycle lanes is a clear effort to promote cycling.

Option 3: "Promotion of car-sharing schemes"

Explanation: This option is incorrect because while car-sharing schemes are mentioned as a popular alternative to private car ownership, they do not relate to cycling safety or appeal. The text does not connect this initiative to the specific goal of enhancing cycling.

Option 4: "Reduction of carbon emissions through public transport"

Explanation: This option is incorrect as it refers to the broader initiative of reducing carbon emissions through public transport, which includes electric buses. However, it does not specifically address the initiative aimed at making cycling safer and more appealing, thus failing to answer the question.