What kind of mutation would lead to an increase in the expression (or inappropriate expression)of a gene?

A) A mutation that lowers the efficiency of a repressor of the gene
B) A mutation that lowers the efficiency of an activator of the gene
C) A mutation that increases the efficiency of a repressor of the gene
D) A mutation that mutates an activator for the gene such that promoter recognition decreases
E) A mutation that mutates a repressor for the gene such that promoter recognition increases