Nodal planes of π -bond(s) in CH2=C=C=CH2 are located in :
a. all are in molecular plane
b. two in molecular plane and one in a plane perpendicular to molecular plane which contains C—C σ -bond
c. one in molecular plane and two in plane perpendicular to molecular plane which contains C—C σ -bonds
d. two in molecular plane and one in a plane perpendicular to molecular plane which bisects C—C σ -bonds at right angle