Explanation

This is an equal-surface-area volume-ratio problem. Let both have surface area S. For the sphere, S = 4πr² gives r = √(S/4π) and V_sphere = (4/3)πr³; for the cube, S = 6a² gives a = √(S/6) and V_cube = a³. Then V_sphere²/V_cube² = [(4/3)π]²(S/4π)³/(S/6)³ = 6/π, i.e. the ratio is 6:π. Option (d) 1:1 is the trap from assuming equal surface area means equal volume — the sphere always encloses more. Hence option (a).