The scheme failed for want of adequate funds.

The correct answer is D. sufficient.

The word “sufficient” means “enough or as much as is needed.” In the sentence “The scheme failed for want

of adequate funds,” the word “adequate” means “enough or as much as is needed.” Therefore, the scheme failed because it did not have enough funds.

The other options are not correct because they do not mean “enough or as much as is needed.” The word “necessary” means “required or essential.” The word “recommended” means “suggested or advised.” The word “required” means “obligatory or essential.”

Here are some examples of how the word “sufficient” can be used in a sentence:

• I have sufficient money to buy a new car.
• The amount of food was sufficient for all the guests.
• The teacher gave the students sufficient time to complete the assignment.
• The company has sufficient resources to meet its goals.