Two laboratory compaction curves $($A and B$)$ for the same soil using different compaction efforts are given in Fig.

$(1)$ Which curve is obtained using higher compaction effort? Explair.

$(2)$ Determine the optimum water contents according to both compaction curves. Why does the same soil have different optimum water contents?

$(3)$ According to compaction curve A$,$ if the specification requires the relative compaction of the soil being $\backslash (97\backslash \%\backslash ),$ determine the allowable range of water content of the soil during field compaction.

$(4)$ Is it possible that the data points of a compaction test are located on the right side of the zero$-$volume curve? Explain