The correct answer is d. Egypt and Syria launched a surprise attack against Israel.
The Yom Kippur/Ramadan war was an armed conflict between Israel and the Arab nations of Egypt and Syria in October 1973. The conflict initiated when the coalition of Egypt, led by the president Anwar Sadat, and Syria, led by the president Hafez Al-Asad, launched a surprise attack against Israel during the Yom Kippur holiday, which that year happened to be also during the Islamic sacred month of Ramadan. The goal for the Arab nations was to recover Arab territories that were lost in previous wars against Israel: the Sinai for Egypt and the Golan Heights for Syria.