$($c$)$HRCO Pty Ltd granted each of its $150$ employees $600$ share options on $1$ January $2017.$ Each share option had a fair value was P$20.$ Each grant is conditional upon the employee working for HRCO Pty Ltd until $31$ December $2019.$

Required

Calculate the cost that will be recognised in the financial statements for each of the three years to $31$ December $2019$ if:

$($a$)$No employees leave in the three$-$year period

$($b$)$

a$.$During $2017$ five employees leave and HRCO Pty Ltd$.$ The employees estimated to leave between $2017$ and $2019(3$ year period$)$ is $20\%.$

b$.$During $2018$ a further six employees leave. HRCO Pty Ltd now estimates that during the $3-$ year period $25\%$ of employees will leave.

During $2019$ a further three employees leave