Percentage passing sieve no 200 = 20% , Liquid limit = 5% and N.P , the classification of this soil according to the AASHTO Method is:a.A-2-4b.A-6c.A-2-6d.None

The AASHTO Soil Classification system classifies soils into seven primary groups, named A-1 through A-7, based on their relative expected quality for road embankments, sub-grades, sub-bases, and bases. Some of the groups are then divided into subgroups, such as A-1-a and A-1-b. Furthermore, a Group Index may be calculated to quantify a soil's expected performance within a group.

In this case, the soil has a percentage passing sieve no 200 of 20% and a liquid limit of 5%. The liquid limit is less than 35%, and the percentage passing sieve no 200 is less than 35%. According to the AASHTO Soil Classification system, this soil would be classified as A-1.

However, the options provided do not include A-1. Therefore, the correct answer is d. None.