You are tasked with writing a program that outputs a customization message based on the time of day. Which code snippet correctly uses branching to output 'Good morning!' when the variable 'currentTime' is less than 12?
if (currentTime < 12) { print('Good morning!'); }
if (currentTime = 12) { print('Good morning!'); }
if (currentTime > 12) { print('Good morning!'); }
if (currentTime == 12) { print('Good morning!'); }