Pinolenic acid $(C_{17}{H}_{29}C{O}_{2}H)$ is an unbranched carboxylic acid with three cis alkene groups. It is found in pine nuts and is sometimes used in weight loss regimens as a hunger suppressant. Not every mass spectrometry technique requires ionization through ejection of single electrons; some instruments rely instead on milder ionization methods such as protonation or deprotonation to form charged species. Mass spectra of pinolenic acid were collected in positive ion mode $($using concritions facilitating protonation$)$ and in negative ion mode $($using conditions facilitating deprotonation$).$ A small amount of ozone was present in both experiments. Significant peaks in positive ion mode included $\frac{m}{z}=279,211,171,$ and $117.$ In the absence of ozone, however, only the peak at $279$ remains $($Anal$.$ Chem. $2011,83,4738-4744.$

$14\mathrm{.}83$

Identify the correct structure of pinolenic acid $($each drawing has the formula $C_{17}{H}_{29}C{O}_{2}H).$

Identify the correct structure of pinolenic acid $($each drawing has the formula $C_{17}{H}_{29}C{O}_{2}H).$