Answer:
Melissa cannot deduct any of the costs related to her sightseeing trip because it was not business related.
Explanation:
She can still deduct the costs related to her business activities, since the primary reason of the trip was for business.
The only expenses she can deduct are $250 (registration) + $400 (airfare) + $900 (lodging for 3 nights) + $100 (50% of meals) + $150 (cab fare) = $,1800
Any additional expenses related to non-business activities cannot be deducted as business expenses.