The correct options are
B Extending help to the projects that work to provide safe and clear drinking water.
D Extending help to the projects that work to provide adequate waste disposal.
The members of the World Health Organisation (WHO) extend help to the projects that work to provide safe and clean drinking water, and adequate waste disposal. For example, it declared the decade between 1981 and 1990 as the “International Drinking Water Supply and Sanitation Decade”.