The correct option is C Both a and b
All varieties of orchids do not offer floral rewards to their insect pollinators. For example, the Mediterranean orchid, Ophyrs, employs sexual deceit to aid pollination by a bee species.
This is possible as a petal of its flower bears an uncanny resemblance to the female of the bee in size, colour and markings.
The male bee is attracted to the apparently perceived female, pseudo copulates with the flower, and in that process pollinates the flower.