All except which of the following bats are common in Pennsylvania?

The Indiana bat is considered endangered and is not as commonly found in Pennsylvania compared to the other species listed. While it does occur in the state, it is significantly less prevalent and has specific habitat requirements, which limits its population more than the others. The Big brown bat, Little brown bat, and Northern long-eared bat are all more frequently encountered throughout Pennsylvania. The Big brown bat is adaptable to urban environments, the Little brown bat was once very common before its population decline due to white-nose syndrome, and the Northern long-eared bat, while also affected, is still found in various areas. Therefore, the Indiana bat stands out as the one that is less commonly encountered in the state, making it the correct choice in this context.