The correct answer is: Arabic.
Arabic was added as the sixth official language of the United Nations in 2010. The other five official languages are Chinese, English, French, Russian, and Spanish.
Arabic is the official language of 26 countries in the Middle East and North Africa. It is also spoken by significant populations in other countries, such as France, Germany, and the United States.
Arabic is a Semitic language that is written from right to left. It is a very complex language with a rich history and culture.
The decision to add Arabic as an official language of the United Nations was made in response to the growing importance of the Arab world in the international community. Arabic is now the most widely spoken language in the United Nations, after English.
The addition of Arabic as an official language has made it easier for Arab countries to participate in the work of the United Nations. It has also helped to promote understanding and cooperation between the Arab world and the rest of the world.
The other options are incorrect because they are not official languages of the United Nations. Chinese, Spanish, and Russian are all official languages of the United Nations, but they were added before Arabic.