ashiquzzaman on "Default Layouts not showing on frontend on theme activation"

I have set the default layout, so that on theme activation the default layouts shows on front-end without having to save anything in the database. But the problem is the default layouts doesn't show on theme activation. It shows blank page.

//File - default.php
<?php function prefix_option_defaults() {

//default values
$defaults = array(
    'frontpage_layouts' => 'layout_3',
);

  $options = get_option('prefix',$defaults);

  //Parse defaults again - see comments
  $options = wp_parse_args( $options, $defaults );

return $options; }

Calling the defaults at the top of header.php file

//File - header.php
global $prefix;
$prefix= prefix_option_defaults();

Here's the code I'm calling the layouts from -

//File - landing-page.php
if ( get_option( 'frontpage_layouts' ) === 'layout_1' ) {

       get_template_part( 'frontpage/content', 'cta' ); }

    elseif ( get_option( 'frontpage_layouts') === 'layout_2' ) {

        get_template_part( 'frontpage/content', 'cta2' ); }

    elseif ( get_option( 'frontpage_layouts' ) === 'layout_3' ) {

        get_template_part( 'frontpage/content', 'cta3' ); }

    else ( get_option( 'frontpage_layouts' ) === NULL ); {

         get_template_part( 'frontpage/content', 'cta3' ); }

My customizer options are saved as -

get_option('frontpage_layouts')