API gravity is a measure of the density of crude oil compared to water. It is defined by the formula:
\[
{API Gravity} = \frac{141.5}{{Specific Gravity}} - 131.5
\]
For crude oil denser than pure water (specific gravity greater than 1), the API gravity will be less than 10°.
- Option (A) is correct because if the oil is denser than water, the API gravity will be less than 10°.
- Option (B) and Option (C) would apply to less dense crude oils.
- Option (D) applies to lighter oils with API gravity greater than 60°.
Thus, the correct answer is option (A).