var myObject = {
  name1: {
    title: 'Mr',
    options: ['A', 'B', 'C'],

  },
  name2: {
    title: 'Mrs',
    options: ['C', 'D', 'E'],

  }
};

function myFunction(optionSearch) {
  console.log(optionSearch);
  for(var i in myObject) {
    if (myObject[i].options.indexOf(optionSearch) >= 0)
      console.log(i + ' is equal to optionSearch');
    else {
      console.log('No match');
    }
  }
}

Object.keys(myObject)
  .filter((key) => {
    return myObject[key].options.includes(optionSearch)
  })