Pfizer employs a strategy focused on demand$-$side tactics to establish obstacles for potential competitors. Pfizer is trying to:

a$)$ prevent new entrants from attracting any of the seller's customers.

b$)$ encourage the government to use regulations to discourage new entrants.

c$)$ increase market demand so that there are extra customers for the new entrants.

d$)$ ensure that new entrants face higher cost curves.