Chapter SRP, Problem 12P

The remaining steps in the industrial synthesis of vitamin A (as an acetate) are as follows: the Grignard reagent C from Problem 11 is allowed to react with the aldehyde shown here:

After acidification, the product obtained from this step is a diol (D). Selective hydrogenation of the triple bond of D using ${\text{Ni}}_{\text{2}}\text{B}$ (P-2) catalyst yields E $\left({\text{C}}_{\text{20}}{\text{H}}_{\text{32}}{\text{O}}_{\text{2}}\right)$. Treating E with one molar equivalent of acetic anhydride yields a monoacetate (F), and dehydration of F yields vitamin A acetate. What are the structures of D–F?