The correct option is 1 and 3 only because "Water Credit" indeed leverages microfinance mechanisms to facilitate access to water and sanitation services for impoverished communities, allowing them to invest in these essentials without reliance on government subsidies. However, while it is a global initiative, it is not directly launched under the aegis of the World Health Organization (WHO) and the World Bank; it is instead often promoted by various NGOs and microfinance institutions. Understanding this initiative is essential in the context of sustainable development goals, particularly in improving water access and sanitation for marginalized populations.