A sphere is placed in a cone of height $8.4 \;cm$ The volume of the sphere if it touches the lateral surface and the base of the cone is _____ $cm^3$

Question

$(A) \; 30\; \pi \;cm^3 \\(B)\;25\;\pi \;cm^3 \\(C)\;35 \; \pi \;cm^3 \\(D)\;29 \;\pi \;cm^3$