Employees stock option scheme

In a problem in ICAI text book .,It was mentioned that inorder the share price rises above 70/- in  year 2016-17 the options will vest., but the price doesn't cross 70/- as mentioned above., reaches 68/-...it was mentioned the actual vesting is nil., and however the company should recognise the expense over three year vesting period., kindly explain me why? I mean why it should be recorded in accounts even the though the options doesn't vest....