Which one of the following correctly describes the graph of y=logax when 0<a<1?
a) Passes through (1,0), increases, and is concave downward
b) Passes through (1,0), decreases, and is concave upward
c) Passes through (0,1), decreases, and is concave upward
d) Passes through (1,0), decreases, and is concave downward