Follow this link. There are some suggestions on which A level program to choose.
Also, have a look at the list of the A-level colleges in Nepal in the link below:
Hey Annonymous, good to hear that you are crazy to study A-levels at Budhanilkantha School. But keep in mind that BNKS is not the only place where you would be offered quality education. I was lucky to continue my schooling at BNKS right from class 4 to A-levels. The school not only offers quality education but helps you to be an individual!
If you are really really crazy, then I suggest you ask for an appointment with the Principal, Mr. Keshar Khulal. Three years ago a similar thing happened. One of my friends was selected for +2 but he talked with the principal and got the opportunity to pursue A-levels. We were surprised to see him in the class and by the decision. But that decision paid off, he was Nepal topper in the recently concluded May-June A-levels Examination.