A marble of mass \[x\] and diameter 2r is gently released in a tall cylinder containing honey. If the marble displaces mass y (< \[x\]) of the liquid, then the terminal velocity is proportional to

• A. \[x+y\]
• B. \[x-y\]
• C. \[\frac{x+y}{r}\]          
• D. \[\frac{x-y}{r}\]