//1

<select name="phone_number_type[]">
<option value="1">Mobile</option>
<option value="2">Home</option>
<option value="3">Work</option>
</select>

<input type="text" name="phone_number[]" />

//2

<select name="phone_number_type[]">
<option value="1">Mobile</option>
<option value="2">Home</option>
<option value="3">Work</option>
</select>

<input type="text" name="phone_number[]" />

//3

<select name="phone_number_type[]">
<option value="1">Mobile</option>
<option value="2">Home</option>
<option value="3">Work</option>
</select>

<input type="text" name="phone_number[]" />