The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
A woman must have permission and an escort to attend the Hajj because that is what the Muslim religion stated in its religious principles. Muslim law establishes that any woman below 45 years old that wants to make the trip to Mecca to participate in Hajj, must be accompanied by a male chaperon that is going to serve as a guardian. Otherwise, women can't attend this Muslim tradition. Women who are older than 45 can make a trip in groups, but they need a notarized letter authorized by the husband or son.
That is how strict Muslim law is to women.