Which of the following has the most acidic proton [Roorkee Qualifying 1998]

• A. \[C{{H}_{3}}COC{{H}_{3}}\]
• B. \[{{(C{{H}_{3}})}_{2}}C=C{{H}_{2}}\]
• C. \[C{{H}_{3}}COC{{H}_{2}}COC{{H}_{3}}\]
• D. \[{{(C{{H}_{3}}CO)}_{3}}CH\]