Final answer:
Cathy's chance of the payment not being secure increases if the desired watch is not available in local stores.
Step-by-step explanation:
The correct answer is c) The unavailability of the desired watch in local stores. The unavailability of the desired watch in local stores increases Cathy's chance of the payment not being secure because it may lead her to take risks and purchase from an unknown or untrusted online store. When a product is not available locally, there is often a greater sense of urgency to find it online, which can lead to making impulsive decisions and overlooking important security factors. Therefore, it is important for Cathy to exercise caution and thoroughly research the online store before making a purchase.
While options a) Using a secure payment gateway, b) Purchasing from a reputable online store, and d) Checking customer reviews can all contribute to ensuring a secure payment, the unavailability of the desired watch in local stores carries a higher risk due to the factors mentioned above.