Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to create a mockup of your app idea by yourself [title] Provide a brief but a clear description of your idea which includes the purpose, scope, goal and other assumptions. [title] Target a niche group of audience for your app. [step] This is to get the best out of your app and know all it's pros and cons inside out.

Ending1: Therefore, describe the target demographic of your app, your potential customers. [title] Create an interactive prototype of your app. Ending2: Don't rely purely on your friends to have the ball rolling; target the resources needed to take all the shape. Also, don't be shy about making a list. Ending3: In order to give your app the unique brand name and visual appeal, you need to work on the style and content that surrounds it. [substeps] If your app can be hidden on wikipedia, bring it out in west west. Ending4: The range from 15 to over 1500 people is for start you go. Build a stable audience with a good idea of the goals and objectives of your app.

Answer format: ending1/ending2/ending3/ending4