A small child is at a candy store, eager to spend his $1 allowance on candy. His two favorite candies are priced at $0.05 and $0.10, respectively. If the child is intent on spending his entire allowance on candy, which of the following represents a standard form equation that describes this situation?
a.  0.05x 0.10y=1.00
b.  0.10x-0.05y=1.00
c.  5x 10y=100.00
d.  x 2y=20.00