Which organic product is formed when 2-phenylethanol is heated under reflux with excess acidified potassium dichromate(VI)?
C6H5CH2CHO\text{C}_6\text{H}_5\text{CH}_2\text{CHO}C6H5CH2CHO
C6H5CH2COOH\text{C}_6\text{H}_5\text{CH}_2\text{COOH}C6H5CH2COOH
C6H5COCH3\text{C}_6\text{H}_5\text{COCH}_3C6H5COCH3
C6H5COOH\text{C}_6\text{H}_5\text{COOH}C6H5COOH