In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Q: Question: If I can not learn my new phone number because I always see the first three digits of the old one, what is the name of that type of interference?
Options: <1> Proactive <2> Retroactive. <3> Coactive <4> Reactive <5> Protoactive
A:
1