You may have separated the logarithm into two logarithms, but then multiplied instead of adding them. Use the product property, $\displaystyle{\log}_{{b}}{\left({M}{N}\right)}={\log}_{{b}}{M}+{\log}_{{b}}{N}\usepackage{cmbright}\Huge\$ . Then simplify. The correct answer is $\displaystyle{1}+{\log}_{{{4}}}{c}\usepackage{cmbright}\Huge\$ .