How i can use if condition to set options selected on condition matached

Here is my code and in helper i am doing as just for idea i am writing, i am unable to understand how to do that to set the options selected on the base of conditions

‘helper’: function (a,b) {

   return a===b;


it is giving me error also as

" template tag of type BLOCKOPEN is not allowed here.
…h exercises}}<option {{#if helper}} selec… "

{{#each exercises}}<option {{#if helper}} selected {{/if}} >{{name}}</option>{{/each}}