Identify 'X' in above reactions

The following conversion is known as:

Reagents which can be used to convert alcohols to carboxylic acids, are

(A) $$\mathrm{CrO}_3-\mathrm{H}_2 \mathrm{SO}_4$$

(B) $$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7+\mathrm{H}_2 \mathrm{SO}_4$$

(C) $$\mathrm{KMnO}_4+\mathrm{KOH} / \mathrm{H}_3 \mathrm{O}^{+}$$

(D) $$\mathrm{Cu}, 573 \mathrm{~K}$$

(E) $$\mathrm{CrO}_3,\left(\mathrm{CH}_3 \mathrm{CO}\right)_2 \mathrm{O}$$

Choose the most appropriate answer from the options given below :

The major product formed in the following conversion is ___________.