Give the structure that corresponds to the following molecular formula and NMR spectra: C6H14O 1H NMR: ? 0.91 (6H, d, J = 7 Hz); ? 1.17 (6H, s); ? 1.48 (1H, s; disappears after D2O shake); ? 1.65 (1H, septet, J = 7 Hz). 13C NMR: ? 17.6, ? 26.5, ? 38.7, ? 73.2.