A. F<sub>1</sub>=3NF<sub>2</sub>=4NF<sub>3</sub>=2NB. F<sub>l</sub>=3NF<sub>2</sub>=1NF<sub>3</sub>=5NC. F<sub>1</sub>=2NF<sub>2</sub>=5NF<sub>3</sub>=10ND. F<sub>l</sub>=5NF<sub>2</sub>=7NF<sub>3</sub>=13N
