This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to get rid of unwanted calls on your cell phone
Download call blocking apps in the play store.
Android users have a number of tools they can access to get rid of unwanted calls in the form of apps, including :
Call filter, a very popular call blocking app that is also free. Droidblock, another android app that can get rid of unwanted calls and is also free.

Pick from:
1). Contact block, an app created on android containing a text messaging sound file that can be downloaded to android versions of the game. Audio messaging, to live chat, videos, and audio albums are popular options..
2). You can use any app, as long as you use it frequently. If your phone is very old, or if your have poor operating systems, you might benefit from using this app instead..
3). Call screening applications, such as free calls apps, you can download and install. Hear a beep indicating that the phone is dead..
4). Keep in mind success with call-blocking apps tend to vary and they are not always 100% effective. Have spam calls sent directly to voicemail..
The answer is:
4).