ANS:D - oven-drying method.

W = weight of water/ weight of solids.

Weight is calculated when water is present and water is absent. The most accurate method is - Oven Drying Method.

Quickest method - Calcium Carbide Method (By this test we can get results within 5min. ). Calcium Carbide usually known as RMM( Rapid Moisture Meter test ) is a field test method.

Oven drying method is a lab method test with proper temp. control. So due to temperature control so the test result is most accurate 24 hr. 105 - 110 degree celsius