In the Period of One Week, Mohammed Can Knit 5

Multiple Choice

In the period of one week, Mohammed can knit 5 sweaters or bake 240 cookies.In period of one week, Tetah can knit 15 sweaters or bake 480 cookies.How can Mohammed and Tetah produce the maximum quantities of cookies and sweaters?  

A)  if Mohammed knits and bakes, and Tetah does nothing 
B)  if Tetah knits and bakes, and Mohammed does nothing 
C)  if Mohammed knits and Tetah bakes 
D)  if Tetah knits and Mohammed bakes