If $a, b, c$ are continued proportional, then $\left(\dfrac{a+b}{b+c}\right)^2$ equals—

Question

Accepted Answer

$\dfrac{a^2+b^2}{b^2+c^2}$

Answer

$\dfrac{a-b}{b-c}$

Answer

$\dfrac{a+c}{2b}$

Answer

$\dfrac{a^2-b^2}{b^2-c^2}$

If a,b,ca, b, ca,b,c are continued proportional, then (a+bb+c)2\left(\dfrac{a+b}{b+c}\right)^2(b+ca+b​)2 equals—