The correct answer is A. 10%.
The Los Angeles abrasion test is a standard test used to determine the resistance of aggregates to abrasion. The test is conducted by placing a sample of aggregate in a rotating drum with steel balls. The drum is then rotated for a specified period of time, and the amount of aggregate that is abraded away is measured.
The maximum allowable Los Angeles abrasion value for high quality surface course is 10%. This means that no more than 10% of the aggregate in the surface course can be abraded away during the test. If the aggregate is abraded away more than 10%, it is not considered to be suitable for use in a high quality surface course.
The other options are incorrect because they are higher than the maximum allowable Los Angeles abrasion value for high quality surface course.