Answer:
i) Investor should buy a call option as expected spot price on SGD after 90 days is 0.7 which less than the strike price 0.65 under call option.
II) Break-even price on option selected
Strike price under call option 0.65000
Add : Premium 0.00046
Break even price 0.65046
iii) Actual spot rate after 90 days 0.70000
Less: Strike price under call option 0.65000
Gross profit 0.05000
Less: Call option premium 0.00046
Net profit 0.04954
iv) Actual spot rate after 90 days 0.80000
Less: Strike price under call option 0.65000
Gross profit 0.15000
Less: Call option premium 0.00046
Net Profit 0.14954