Specialized epidermal cells surrounding the guard cells are called as Complementary cells. Lenticels. Bulliform cells. Subsidiary cells.

Stomata are minute pores which occur on the epidermal surface of leaves and also some herbaceous stems. Each stoma is guarded by two specialised cells, called guard cells. These guard cells are also surrounded by other specialised epidermal cells called subsidiary cells. These cells also play an important role in opening and closing of stomata.So, the correct answer is option B.