Originally Posted by steveholt

4(c) Travel may originate at any point for which fares are published and must terminate at the same point, except that origin‐destination surface segments are permitted as follows:
a. within the country of origin
b. within the Middle East
c. between the United States and Canada
d. between HKG and China
e. between Malaysia and SIN
f. within Africa
g. between Maldives and Sri Lanka/India

So essentially, depending on where you leave from, your final destination can be adjusted accordingly:
- if you leave from one airport in a country, your final leg can be any airport in that country (eg leave LHR, return MAN)
- if you leave from the Middle East, you can return anywhere in the Middle East. (eg leave CAI, return DXB, DOH, etc)
- if you leave from the US or Canada, you can return to any airport in either country (eg leave YVR, return JFK)

I'll leave you to the rest.