Final answer:
The scenario that does not involve potential security threats like a bomb, a suspicious package, or product contamination is opening a gift on your birthday.
Step-by-step explanation:
The scenario that does not involve a bomb found, a suspicious package, or product contamination is b) Opening a gift on your birthday. This is a common social event that typically involves receiving presents from friends and family, which are given with good intentions and are not suspicious in nature.
Therefore, it stands apart from the other scenarios as the most likely to be safe and without malintent. Scenarios like discovering an unattended bag at an airport, receiving a letter from a friend, or finding a misplaced wallet could potentially involve security threats or personal information vulnerability, but opening a birthday gift does not typically correspond with those risks.