The Following Code Snippet Adds an AdView to a Layout

Multiple Choice

The following code snippet adds an AdView to a layout. What does the XML attribute ads:adUnitId refer to? <com.google.ads.AdView android:id="@+id/adView" android:layout_width="wrap_content" android:layout_height="wrap_content" ads:adUnitId="MY_AD_UNIT_ID" ads:adSize="BANNER" ads:testDevices="TEST_EMULATOR, TEST_DEVICE_ID" ads:loadAdOnCreate="true"/>

A) The ID of the device where ads are displayed for testing.
B) The publisher ID as provided by AdMob.
C) The location of the ad in the activity.
D) The Android resource id of the AdView