Options are 25c to exercise, so they should be at least current SP - 25c. SP is 47.5c - 25c is 22.5c. Last trade 19.5c. 3c discount.
Because you have until April 09 to pay the 25c, you pay a premium (in this case maybe 3c), so the options should be around 25.5c if the share price is 47.5c.
Options can lag a bit on a run up, but this gets corrected over time usually...