Which compound can be refluxed with acidified potassium dichromate(VI) to form an organic product with molecular formula C5H8O2\text{C}_5\text{H}_8\text{O}_2C5H8O2?
3-hydroxypentanal
3-methylbutane-1,3-diol
pentane-1,5-diol
pentane-2,4-diol