KhanG Sb.
I would recommend possession available sector A to J and avoid K to M and Extension.
10 Marla and 1 Kanal are better investments. 5 Marla has its limitations when it comes to attracting buyers.
If you have money build house right away, you can rent it. Even if your plot doesn't appreciate in 2 years (highly unlikely) construction cost will increase for sure.
I think DHA II is the best investment in twin city at this point. But this is my opinion and a lot of people might not agree to it.
Good Luck in making the right decision.