Correct option is (a) Frond
To explain I would say: The vegetative cells in Phaecophyceae are made up of two layers with the inner one being made of cellulose and the other being made of gelatinous coating of algin. A leaf like photosynthetic organ in Phaecophyceae is called as frond. They also have a stalk called stipe and a substratum called as holdfast.