A fine-grained soil has $60 \%$ (by weight) slit content. The soil behaves as $\textit{semi-solid}$ when water content is between $15 \%$ and $28 \%$. The soil behaves $\textit{fluid-like}$ when the water content is more than $40 \%$. The $’\textit{Activity}\:’$ of the soil is
1. $3.33$
2. $0.42$
3. $0.30$
4. $0.20$