The diagrams illustrate the arrangements of two isomeric dicarboxylic acids, X and Y. X may be reduced to compound P, which has empirical formula $\text{C}_2\text{H}_5\text{O}$. Y may be reduced to compound Q, which also has empirical formula $\text{C}_2\text{H}_5\text{O}$. Which statement is correct?
- AX is a cis isomer; compound P and compound Q are identical.
- BX is a cis isomer; compound P and compound Q are isomers of each other.
- CX is a trans isomer; compound P and compound Q are identical.
- DX is a trans isomer; compound P and compound Q are isomers of each other.