Verified Answer :

class Phaeophyceae  has a member brown algae . brown algae is a very  important source of algin
,now  the  group of algae is responsible for formation of kelp beds along the North American coasts is also brown algae

Answer: A).Brown algae

A kelp is a seaweed species of brown algae. It is moderate in size and grows in cold regions. It grows in the northwestern United states and northern Europe. It belongs to the Fucaceae family. Kelp consists of many organic and inorganic components like carbohydrates, proteins, phenolic compounds, lipids, magnesium, nickel, silver, phosphorus and iron.