The only unequivocal answer is SAUDI ARABIA. However, there is a border dispute between the United Arab Emirates and Saudi Arabia over the 25 kilometer corridor between Qatar and Emirate of Abu Dhabi. If the UAE's position on this debate is taken as being accurate, the UAE would also border both Oman and Qatar. If the Saudi position on this debate is taken as accurate, then the UAE does not border Qatar and Saudi Arabia is the only right answer.
Qatar, and Oman
United Arab Emirates
Oman
oman
two of them are sultanate of oman and saudi arabia
Brunie, Oman, Qatar, Saudi Arabia, Swaziland, and Vatican City.
Ask the Oman authorities.
United Arab Emirates (UAE) is the country which is bordered by Saudi Arabia, Oman and Persian Gulf.
Saudi Arabia, Yemen, Oman, Qatar, United Arab Emirates, and some count Kuwait as an Arabian peninsula country.
Oman to the south, Qatar to the north, and Saudi Arabia to the south and west.
Sultanate of Oman, also bordered by the United Arab Emirates (UAE)
Seven of those countries are in the Arabian Peninsula: Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates and Yemen.