Answer:
option B. MB/AM=NC/AN
Step-by-step explanation:
we know that
The <u><em>Triangle Proportionality Theorem</em></u> states that if a line is parallel to one side of a triangle and it intersects the other two sides, then it divides those sides proportionally
In this problem
MN is parallel to BC
MN intersect AC and divide into AN and NC
MN intersect AB and divide into AM and MB
so
Applying the Triangle Proportionality Theorem
Rewrite