Final answer:
In Texas, the license required for on-site sewage inspections is the On-Site Sewage Facility (OSSF) Installer License, which is overseen by the Texas Commission on Environmental Quality.
Step-by-step explanation:
To perform on-site sewage inspections in Texas, the required license is c) On-Site Sewage Facility (OSSF) Installer License.
This is mandated by state regulations to ensure that professionals engaged in the installation, repair, or inspection of on-site sewage facilities are properly trained and certified to protect public health and the environment. The Texas Commission on Environmental Quality (TCEQ) is responsible for licensing individuals for these activities. Possessing this license confirms that the individual has met the guidelines and training necessary to perform these inspections safely and effectively.