Answer:
United must prove that copyright is valid to establish infringements.
Step-by-step explanation:
Copyrights are norms established by law to protect the relationship between the creator and the use of his creations, be they artistic, literary or scientific creations, such as texts, books, paintings, music, illustrations, photographs, etc. With the use of copyright the creator of something can prevent the use of its creation as long as it proves that it is the copyright holder of that creation. Based on this, we can conclude that United must prove that copyright is valid to establish infringements.