A junior learner's permit is good for ___ year.

A junior learner's permit in Pennsylvania is valid for one year. This time frame allows new drivers, typically those under 18, to practice their driving skills under certain restrictions, preparing them for the next steps toward obtaining a full driver's license. The one-year duration is designed to provide ample time for supervised driving experience, which is crucial for developing the necessary skills and judgment required for safe driving.

The other options suggest shorter or longer validity periods that do not align with the regulations governing junior learner's permits in Pennsylvania. This specific time frame is important both for ensuring practice and assessment of readiness for unsupervised driving, as well as for transitioning to a junior driver's license once the necessary milestones have been achieved.