Arrangement of sepals & petals with respect to one another is

$\begin{array}{1 1}(A)\;\text{Venation}\\(B)\;\text{Aestivation}\\(C)\;\text{Cohesion}\\(D)\;\text{Adhesion}\end{array}$

The mode of arrangement of sepals or petals in floral bud is called as aestivation
Hence (B) is the correct answer.