"Thank you, Eid Mubarak."
Translation:Terima kasih, selamat idul fitri.
Eid Mubarak is not an English term. It may be an alternate way to say that greeting, but it isn't English.
I don't get the use to teach "Eid Mubarak" to people, which first of all is Arabic, and its translation in Bahasa, as nobody will probably ever use it.
Eid Mubarak is a formula used to wish a happy Eid, in the muslim community all around the world at the different End (one being precisely on the day where I write this: Eid Al-Fitr, the other is Eid Al-Adha), it's like teaching us to say Merry Christmas as a fundamental of English.
Eids are important to the muslim community and Indonesia is the biggest muslim country in the world, but indonesia also has a lot of Indus, Buddhists and Christians and this will only be relevant to the muslim community, two days per year. (and a lot fo them will say Eid Mubarak anyway)
I wrote this exactly as written above, "Terima kasih, selamat idul fitri" and got the message "you used the wrong word."