Error between Really simple captcha and bootstrap for contact form

Add Bellow line of code in :
bootstrap-for-contact-form-7\modules\really-simple-captcha.php File

function wpcf7_captcha_form_tag_handler( $tag ) {
$tag = new WPCF7_FormTag( $tag );

if ( ‘captchac’ == $tag->type && ! class_exists( ‘ReallySimpleCaptcha’ ) ) {
return ‘‘ . __( ‘To use CAPTCHA, you need Really Simple CAPTCHA plugin installed.’, ‘contact-form-7’ ) . ‘‘;
}

if ( empty( $tag->name ) ) {
return ”;
}

$validation_error = wpcf7_get_validation_error( $tag->name );

$class = wpcf7_form_controls_class( $tag->type );

if ( ‘captchac’ == $tag->type ) { // CAPTCHA-Challenge (image)
$class .= ‘ wpcf7-captcha-‘ . $tag->name;

$atts = array();

$atts[‘class’] = $tag->get_class_option( $class );
$atts[‘id’] = $tag->get_id_option();

$op = array( // Default
‘img_size’ => array( 72, 24 ),
‘base’ => array( 6, 18 ),
‘font_size’ => 14,
‘font_char_width’ => 15 );

$op = array_merge( $op, wpcf7_captchac_options( $tag->options ) );

if ( ! $filename = wpcf7_generate_captcha( $op ) ) {
return ”;
}

if ( ! empty( $op[‘img_size’] ) ) {
if ( isset( $op[‘img_size’][0] ) ) {
$atts[‘width’] = $op[‘img_size’][0];
}

if ( isset( $op[‘img_size’][1] ) ) {
$atts[‘height’] = $op[‘img_size’][1];
}
}

$atts[‘alt’] = ‘captcha’;
$atts[‘src’] = wpcf7_captcha_url( $filename );

$atts = wpcf7_format_atts( $atts );

$prefix = substr( $filename, 0, strrpos( $filename, ‘.’ ) );

$html = sprintf(
‘<input type=”hidden” name=”_wpcf7_captcha_challenge_%1$s” value=”%2$s” />‘,
$tag->name, $prefix, $atts );

return $html;

} elseif ( ‘captchar’ == $tag->type ) { // CAPTCHA-Response (input)
if ( $validation_error ) {
$class .= ‘ wpcf7-not-valid’;
}

$atts = array();

$atts[‘size’] = $tag->get_size_option( ’40’ );
$atts[‘maxlength’] = $tag->get_maxlength_option();
$atts[‘minlength’] = $tag->get_minlength_option();

if ( $atts[‘maxlength’] && $atts[‘minlength’]
&& $atts[‘maxlength’] < $atts[‘minlength’] ) {
unset( $atts[‘maxlength’], $atts[‘minlength’] );
}

$atts[‘class’] = $tag->get_class_option( $class );
$atts[‘id’] = $tag->get_id_option();
$atts[‘tabindex’] = $tag->get_option( ‘tabindex’, ‘int’, true );
$atts[‘autocomplete’] = ‘off’;
$atts[‘aria-invalid’] = $validation_error ? ‘true’ : ‘false’;

$value = (string) reset( $tag->values );

if ( wpcf7_is_posted() ) {
$value = ”;
}

if ( $tag->has_option( ‘placeholder’ )
|| $tag->has_option( ‘watermark’ ) ) {
$atts[‘placeholder’] = $value;
$value = ”;
}

$atts[‘value’] = $value;
$atts[‘type’] = ‘text’;
$atts[‘name’] = $tag->name;

$atts = wpcf7_format_atts( $atts );

$html = sprintf(
‘<span class=”wpcf7-form-control-wrap %1$s”><input %2$s />%3$s</span>’,
sanitize_html_class( $tag->name ), $atts, $validation_error );

return $html;
}
}