How to align contact 7 checkbox +Label to center horizontally on the page?

I cant seem to get the checkbox on the contact 7 form in wordpress to align in the center without turning everything in my form centered. I dont know what im doing wrong so if anyone could point me in the right direction i would be grateful.

<div class="row">
        <div class="col-sm-4">
            <div class="form-group">
                <label for="form_name">First Name *</label><input id="form_name" type="text"     name="name" class="form-control" required="required" data-error="name is required.">
                <div class="help-block with-errors"></div>
             </div>
        </div>
        <div class="col-sm-4">
            <div class="form-group">
                <label for="form_name">Last Name *</label><input id="form_name" type="text" name="surname" class="form-control" required="required" data-error="name is required.">
                <div class="help-block with-errors"></div>
            </div>
        </div>
        <div class="col-sm-4">
            <div class="form-group">
                <label for="form_email">Email *</label><input id="form_email" type="email" name="email"  class="form-control" required="required" data-error="Valid email is required.">
                <div class="help-block with-errors"></div>
            </div>
        </div>
        <div class="col-sm-4">
            <div class="form-group">
                <label for="form_phone">Phone Number *</label><input id="form_phone" type="tel" name="phone" class="form-control">
                <div class="help-block with-errors"></div>
            </div>
        </div>
        <div class="col-sm-4">
            <div class="form-group">
                <label>Preferred Contact Method</label>[text PreferredContactMethod "Email/Phone"]
           </div>
        </div>
        <div class="col-sm-4">
            <div class="form-group">
                <label>Desired Moving Date</label>[date DesiredMovingDate] 
          </div>
        </div>
<div class="mb-12">
             <div class="col-md-12 col-lg-12"> <position:center>
                <label>Desired Unit Type</label>[checkbox DesiredUnitType use_label_element "Studio" " 1-Bedroom  " " 2-Bedroom  " "3-Bedroom" "Penthouse"]

          </div>
       </div>
       
       <div class="col-md-12">
                <label>Message</label>[textarea Message]
<div class="col-md-12">[submit class:btn class:btn-default class:btn-sm "Send"]</div>
    </div>
</div>