Question

Can you help me find the pro-noun antecedent agreement.
1) For that person to be sure the friend understands the humor, they might add a winking emoticon, like this ; ).
2 Emoticons are especially useful when someone thinks that what they are writing could be misunderstood.
3)They will use an emoticon to show what facial expressions or hand gestures usually show in a face-to-face conversation
4) For that person to be sure the friend understands the humor, they might add a winking emoticon, like this ; ).