Referring to the contingency table in Problem 4.10, if a marketer is selected at random, what is

Question:

Referring to the contingency table in Problem 4.10, if a marketer is selected at random, what is the probability that
a. He or she plans to increase use of LinkedIn?
b. He or she is a B2C marketer?
c. He or she plans to increase use of LinkedIn or is a B2C marketer?
d. Explain the difference in the results in (b) and (c).