Final answer:
An issued Third-Class Medical Certificate to a 19-year-old pilot expires at midnight on August 10, 2 years later.
Step-by-step explanation:
The correct answer is August 10, 2 years later (option a).
In aviation, a Third-Class Medical Certificate is issued to pilots who are seeking to exercise the privileges of a recreational or private pilot certificate.
The Third-Class Medical Certificate is valid for a duration of 5 years for pilots under the age of 40. However, if the pilot is 40 or older, the certificate is only valid for 2 years. In this case, the pilot is 19 years old, so the medical certificate will expire at midnight on August 10, 2 years later.