Answers for "The prefix "tools" for attribute "tools:replace" associated with an element type "application" is not bound"

The prefix "tools" for attribute "tools:replace" associated with an element type "application" is not bound

Did you add the xmlns:tools="http://schemas.android.com/tools" inside 
AndroidManifest.xml?

Specifically,

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.YOUR_APP_NAME"
    android:versionCode="2"
    android:versionName="2.0.1">