i know php lanuage but now i am working in seo.so what would be the better option for my carrier php or seo or?

Actually i know php lanuage for web programming but now i am working in seo.So tell me what will be better choice for my future. php or seo

both are best field but it depend on you which field is your specialization. if your are a good php programmer than you earn good salary. and if you are best in seo than you start own business because seo company pay you a little bit salary if you doing own business than you earn martingales salary.....