Which of the following is the correct syntax for making an option the default selected value for a drop-down list in a form?

<option value="Option1" default>Option 1</option>

<option value="Option1" select>Option 1</option>

<option value="Option1" selected="true">Option 1</option>

<option value="Option1" default="true">Option 1</option>

<option value="Option1" selected>Option 1</option>