Who do i write the scholarship letter to? Ten points?

okay i won a schlorship contest and this scholarship was a community scholarship so there were more than one donors and more than one winners. but each winner had a specific donor. the scholarship community is run by president John. so anyways my question is how or who should i think and who should i make my main subject , the president of the scholorship community or the donors and my donor mechanics bank president (i don't know his name). also to make things worst i left the banquet early because my mom was sick and i did not notify anybody i was going to leave. so anyways how do i write the thank you letter to thankthe donors and to explain why i left early? thank you