For the given function, find f(23), f(60), f( 31), and f( 129). f(x)=x+4 Find f(23). Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. f(23)= 3 (Simplify your answer.) OB. The root is not a real number. Find f(60). Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. f(60) 4 (Simplify your answer.) OB. The root is not a real number. Find f(-31). Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. f( 31) = (Simplify your answer.) B. The root is not a real number.