Following are the results of a sieve analysis:

Sieve No.	Percent Finer
4	99
10	87
20	77
40	65
60	32
80	23
100	14
200	7
Pan	-

(a) Plot the grain-size distribution curve for this sample.
(b) Determine D₁₀, D₃₀, and D₆₀.
(c) Calculate the uniformity coefficient, C_u.
(d) Calculate the coefficient of gradation, C_c.