Answer:
Es
Step-by-step explanation:
First, let's compare es and está.
Es (from the verb ser) is used for what something is. For example, occupation, characteristics, nationality, religion, relationships and more.
Está (from the verb estar) is used for how something is. Some examples are emotions and location.
Now, let's examine our sentence.
Mi familia _______ católico ⇒ My family _____ Catholic
As previously mentioned, ser/es can be used for religion. Therefore, the best answer choice is es.
Mi familia es católico ⇒ My family is Catholic