A food co-op sells a homogenous good called groceries, denoted g. The co-op's cost function is described by: C(g)=F+cg; where F denotes fixed cost and c is the constant per unit variable cost. At a meeting of the co-op board, a young economist proposes the following marketing strategy: Set a fixed membership fee M and a price per unit of groceries p_M that members pay. In addition, set a price per unit of groceries p_N higher than p_M at which the co-op will sell groceries to non-members. Which type of price discrimination is this?

Second degree price discrimination

First degree price discrimination

It is not price discrimination

Third degree price discrimination