ReactJS - Clear select value on focus

I need to clear the selected value of select dropdown as soon as user focus on the select element. I have used the below code but cant figure out what property of select do I need to reset.

<select name="select1" onChange={this.onChangeOption} onFocus={this.handleFocus}>
    <option value=''>Please select...</option>
    <option value='A'>A</option>
    <option value='B'>B</option>
    <option value='C'>C</option>
    <option value='D'>D</option>
</select>

handleFocus(event) {
    event.target.select(); // it did not work!!
}

I want the selected value to be Please select... when the user focuses on the element.