The correct option is
B
Rhombus
Let ABCD be a parallelogram circumscribing a circle with centre O and touching at P, Q, R and S.
∴ AB=CD and BC=AD(∵ Opposite sides of a parallelogram are always equal)
Since, the lengths of tangents drawn from an external point are equal.
⇒AP=AS ....(i)⇒BP=BQ ....(ii)⇒CR=CQ ...(iii)⇒DR=DS ...(iv)
Adding (i), (ii), (iii) and (iv), we get
AP + BP + CR + DR = AS + BQ + CQ + DS
⇒AB+CD=AD+BC⇒ AB+AB=BC+BC (∵ AB=CD and BC=AD)⇒AB=BC⇒AB=BC=CD=DA
Therefore, ABCD is a rhombus.
Thus, a parallelogram circumscribing a circle is always a rhombus.
Hence the correct answer is option b.