Texts back as soon as possible:
ESTJ, ESFJ, ENFJ, ENTJ, ISTJ, ISFJ
Replied in their head and didn't realise they didn't actually reply:
ENFP, ENTP, INFJ, INFP, INTP, ISFP
Saw it and told themselves they'll do it later:
ESTP, ESFP, ISTP
Reads it and doesn't bother to reply:
INTJ
