Correct option is (A) 2
AD is angle bisector of \(\angle A\) which meet BC at D.
\(\therefore\) \(\frac{BD}{DC}=\frac{AB}{AC}\) (By internal angle bisector theorem)
\(\Rightarrow\) \(AB=AC.\frac{BD}{DC}\)
\(=3.5\times\frac47\)
\(=0.5\times4=2\) \((\because \frac{BD}{DC}=\frac47\;\&\;AC=3.5\) (given))