Why does AFN$/$EFR formula provide different estimate of additiona financiang needed compared with the Percentage$-$of$-$Sales method?

Question $1$ options:

B$.$ Percentage$-$of$-$Sales method assumes that retention ratio stays constant, while AFN formula method does not make that assumption

D$.$ AFN formula method calculates spontaneous increase in liability in a different way

A$.$ AFN formula method assumes that profit margin stays constant, while Percentage$-$of$-$Sales method does not make that assumption

C$.$ AFN formula method calculates the required increase in assests in a different way