Let the length be l and the breadth be b.
$$frac{l}{b}=frac{4}{3}$$
$$b=frac{3 imes l}{4}$$
Also, $$2 imes left(l+b ight) = 112$$
$$l+b = 56$$
$$l+frac{3 imes l}{4}=56$$
$$frac{7 imes l}{4}=56$$
$$l=8 imes4=32$$
$$b=56-32=24$$
Area of Rectangle=$$l imes b=32 imes 24=768.$$
Hence option B is the correct answer.