find controller that loads particular phtml file

Question

im new to this, where can i find the php controller code that loads the following template file in:

<reference name="product.info.options.wrapper">
    <block type="catalog/product_view_type_configurable" name="product.info.options.configurable" as="options_configurable" before="-" template="catalog/product/view/type/options/configurable.phtml"/>
</reference>

Answer 1

Controllers do not load templates.
Controllers load layout handles that contain blocks that are rendered by template.
The xml section you posted means is located in the layout handle PRODUCT_TYPE_configurable.
this layout handle is loaded by
Mage_Catalog_Helper_Product_View::initProductLayout() that is called by Mage_Catalog_Helper_Product_View::prepareAndRender() that is called by Mage_Catalog_ProductController::viewAction(),
but only when viewing a configurable product.
So the controller you are looking for is Mage_Catalog_ProductController.