A.I. Explanation:

Option 1: "To introduce a new form of digital payment"

Explanation: While the Eco Transit System includes a Smart Card for digital payments, this is not the main goal of the initiative. The text emphasizes reducing traffic congestion and carbon emissions, which are broader objectives than just introducing a payment method.

Option 2: "To encourage the use of electric vehicles only"

Explanation: This option incorrectly narrows the focus to electric vehicles alone. The Eco Transit System aims to promote sustainable urban mobility through various means, including public transport and bicycle lanes, not just electric vehicles.

Option 3: "To enhance public transport and reduce car use"

Explanation: This option accurately reflects the main goal of the Eco Transit System as stated in the text. The initiative is designed to reduce traffic congestion and carbon emissions, which involves enhancing public transport and aiming for a 30% reduction in private car use by 2025.

Option 4: "To expand the city's bicycle lane network"

Explanation: Although expanding bicycle lanes is a component of the Eco Transit System, it does not capture the main goal. The primary aim is to enhance public transport and reduce car use, which encompasses more than just the bicycle lane expansion.