The correct answer is D. Soluble.
The other three words, loveable, manageable, and usable, are all spelled correctly.
Soluble is an adjective that means able to be dissolved in a liquid. It is derived from the Latin word solubilis, which means "capable of being dissolved."
The word soluble is often used in chemistry to describe substances that can be dissolved in water. For example, salt is soluble in water, which means that it can be mixed with water to form a solution.
The word soluble can also be used in a more general sense to describe anything that can be dissolved. For example, a soluble problem is one that can be solved.
The word soluble is spelled with one "l" and one "b." The word "soluble" is often misspelled as "solvable," which is incorrect.
