The expense related to the share options granted to employees is recognized over the service period, which in this case is a two-year period. In 2018, Tucan recognized an expense of 37,500. If, as of 1 January 2019, Tucan estimates that the total shareholder return target will not be met by 31 December 2019, it would indicate that the remaining service period is no longer relevant for the vesting of the options. As a result, any remaining unamortized expense should be reversed.

Since the options are not expected to vest, there would be no additional expense recognized in 2019. Instead, the previously recognized expense of 37,500 would be reversed, effectively reducing the cumulative expense to zero. Therefore, the correct answer is:

C. (75,000) for expense in 2019 and 0 for cumulative expense

This implies that the expense for 2019 would be a reversal of the full amount recognized in 2018, and the cumulative expense would be reduced to zero as the options are now considered to be forfeited.