Which answer describes the simpler problems that could be used to solve this story problem?

wendy's sister had $12 and wendy had twice as much money as her sister. wendy spent $4 at the market and $3 at the newspaper store. how much money did wendy have left?

a.
calculate how much money wendy has to start with. add up the money she spent. add the amount wendy spent to the amount she started with.

b.
calculate how much money wendy spent. add this to the number of items she bought. subtract this sum from the amount of money wendy's sister has.

c.
calculate how much more money wendy had than her sister add up the money wendy spent. subtract the two amounts.

d.
calculate how much money wendy has to start with. add up the money she spent. subtract the amount wendy spent from the amount she started with.