m stuck after creating the two dimensinal array! tried creating a loop and condition statments

var quiz = [
['What is England capital Name?', 'london' ],
['What is currency used in UK?', 'pound'],
['Where does the Jorden river end up?', 'deadsea']
];
var question;
var answer;
var correctAnswer= 0;

function print(message) {
  document.write(message);
}
function printResult(){
  for (var i = 0; i< quiz.length; i+=1){

var question = prompt (quiz[i][0]);
var answer = quiz[i][1];
if (question === answer){
  checkAnswer= answer.toLowerCase;
  correctAnswer +=1;
  print('you got '+ correctAnswer +' right.You have answered these questions correctly');
  print(quiz[i][0]);

}   else {
print ('You got '+ correctAnswer + ' wrong. have got these questions wrong ');
  print(quiz[i][0]);

}  
}
}
printResult();