Answer:[tex]\Huge \boxed{C=15}[/tex]Step-by-step explanation:To solve this problem, first you have to isolate it on one side of the equation. Remember to simplify, subtraction property of equality is subtracting both sides of an equation by the same number it doesn't change the equation.First, subtract 6 from both sides.[tex]\displaystyle \frac{2}{5}c+6-6=12-6[/tex]Solve.[tex]\displaystyle 12-6=6[/tex][tex]\displaystyle \frac{2}{5}c=6[/tex]Next, multiply 5 from both sides.[tex]\displaystyle 5\times\frac{2}{5}c=6\times5[/tex]Solve.[tex]\displaystyle 6\times5=30[/tex][tex]\displaystyle 2c=30[/tex]Then, divide by 2 from both sides.[tex]\displaystyle \frac{2c}{2}=\frac{30}{2}[/tex]Solve.[tex]\displaystyle 30\div2=15[/tex]In conclusion, the correct answer is c=15.Hope this helps!Have a wonderful blessing day! :)Good luck! :)