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

How to respond to incoming calls with a message on an iphone
Receive a call on your iphone.
You'll see the option to respond with a text message when you get an incoming call.
Tap the message button on the incoming call screen.

Available choices: -- This will select a contact from the choices to your left. Tap the off button to disconnect from the call, and your iphone will launch a message or chat screen.; -- This button looks like an icon that resembles a phone receiver. Tapping on it will launch an sms message window.; -- This looks like a message bubble, and can be found on the right side of the screen, above the slide to answer or accept button. Tap one of the preconfigured messages.; -- It's at the bottom of the screen. You can even swipe down to find the call form by tapping the gear icon on the bottom of the screen.;
The answer is:
This looks like a message bubble, and can be found on the right side of the screen, above the slide to answer or accept button. Tap one of the preconfigured messages.