The correct option is B Unisexual flower
Inflorescence refers to the arrangement of flowers or cluster of flowers on the stem. Cyathium inflorescence is characterized by a condensed floral axis that forms a cup-shaped structure and unisexual flowers in cymose clusters. Hypanthodium inflorescence is characterized by the floral axis being fleshy and closed forming a pear shaped receptacle. Flowers are unisexual in cymose clusters. However, in Cyathium there is the presence of involucre with nectary gland. The similarities between these two inflorescence is the presence of unisexual flowers.