The share of kindergartens among all schools in a province was 10\% in 2000 and 15\% in 2010. Of the 50 schools opened in this province between 2000-2010, 20 are kindergartens.
Accordingly, how many kindergartens were there in this province in 2000?
A) 30
B) 40
C) 20
D) 25
E) 35