What economy includes a laissez-faire ideal with government involvement to ensure competition fairness and protects public interest?
a. communism
c. socialism
b. mixed economy
d. republic

Generally speaking, it would be a "mixed economy" that includes a laissez-faire ideal with government involvement to ensure competition fairness and protects public interest, since this is between a purely market and purely command economy. 

If u can translate that to english i will surely you!