James came back from Overseas to seek full-time employment in Singapore. He has the following stock options which were granted to him in 2021 and 2022: In 2021, a stock option for 10,000 shares at an exercise price of $1.00 each was granted to James when he was working in Canada In 2022, a stock option for 25,000 shares at an exercise price of $1.50 each was granted to him. 50% of these shares had a sales restriction of 24 months from the date of exercise. James exercised all of his options on 31 December 2022 when the shares were trading at $3.00 each. What is James's total taxable stock option income for the year of assessment 2023?