Consider the following function: f left parenthesis x right parenthesis equals open curly brackets table attributes columnalign left columnspacing 1.4ex end attributes row cell fraction numerator x squared minus 3 x minus 18 over denominator x minus 6 end fraction end cell cell i f space x not equal to 6 end cell row 7 cell i f space x equals 6 end cell end table close Determine if f left parenthesis x right parenthesis is continuous at x equals 6. If not, select the option with the correct reasoning as to why not. a.) Continuous at x equals 6 b.) Not continuous at x equals 6 because limit as x rightwards arrow 6 of f left parenthesis x right parenthesis does not exist c.) Not continuous at x equals 6 because limit as x rightwards arrow 6 of f left parenthesis x right parenthesis not equal to f left parenthesis 6 right parenthesis d.) Not continuous at x equals 6 because f left parenthesis 6 right parenthesis is undefined