For uniformly graded soil, the coefficient of uniformity is:

Correct option is A

​$$\text{The coefficient of uniformity } (C_u) \text{ is defined as:}$$
$$C_u = \frac{D_{60}}{D_{10}}$$
$$\text{For a uniformly graded soil:}$$ $$\text{Most particles are of nearly the same size}$$
$$D_{60} \approx D_{10}$$
$$\text{Therefore,}C_u \approx 1$$​​​​​​