An ester with the molecular formula C8H16O2\text{C}_8\text{H}_{16}\text{O}_2C8H16O2 undergoes acid hydrolysis to yield a carboxylic acid P P\,P and an alcohol QQQ. When alcohol Q Q\,Q is heated under reflux with excess acidified potassium dichromate(VI), it is oxidized to a carboxylic acid RRR.
If carboxylic acid P P\,P and carboxylic acid R R\,R are identical, which of the following is the correct IUPAC name for the original ester?
Pentyl propanoate
Propyl pentanoate
Butyl butanoate
Ethyl hexanoate