The following synthetic sequence leads to compound X

Compound C can be obtained by oxidizing compound Y which is $26.20\%$  oxygen (by mass). Treatment of Y with a strong base produces an equimolar mixture of  $Y_1$  and  $Y_2$  by Cannizzaro reaction. In a weakly acidic medium, compound Y turns into $Y_3$ which is $21.22\%$ oxygen (by mass). The structure, $Y_3$ contains 4 six-membered cyclic rings.
(Atomic mass of C=12, H=1, O=16, Na=23 in atomic mass units)