Marbles of diameter $1.4 \;cm$ are dropped into a cylindrical beaker of diameter $7 \;cm$, containing some water. The number of marbles that should be dropped into the beaker so that the water level lines by $5.6\; cm$ is ________

Question

$(A) \; 100 \\(B)\;125 \\(C)\;130 \\(D)\; 150$