Answer: B. All real numbers
Work Shown:
2(3c+3) < 6c+9
6c+6 < 6c+9 .... distribute
6c+6-6c <6c+9-6c .... subtract 6c from both sides
6 < 9 ... note the c terms go away entirely
We're left with a statement that is always true since 6 is always less than 9 regardless of what value of c we pick. So there are infinitely many solutions. Any real number can replace c to get a true statement.