Answer:
A) buy the product in Hong Kong and sell it in Shenzhen so eventually the price in Shenzhen will decrease and the price in Hong Kong will increase
Explanation: when the price of the product in Shenzhen reduces due to the low priced product being sold in same place the high priced is sold, this would even out the demands and the price of that in Shenzhen would be dragged down to be able to compete with that of the low priced.