settings for a really minimal org tree slide

minimal-org-tree-slide.el

;; Some settings seem best achieved with local variables, and some with a hook.
;; Here are some settings that work for me:

;; #+TITLE: Your Title
;; #+AUTHOR: Your Name
;; #+DATE: The Date of the Talk
;; #+OPTIONS: toc:nil
;; #+OPTIONS: email:nil
;;
;; [Actual talk content goes here] 
;;
;; #+C Local Variables:                        
;; #+C org-confirm-elisp-link-function: nil    
;; #+C org-tree-slide-skip-outline-level: 2    
;; #+C mode-line-format: nil                   
;; #+C eval: (org-tree-slide-mode)
;; #+C eval: (org-display-inline-images t t)
;; #+C eval: (setq org-tree-slide-header nil)
;; #+C End:

(require 'org-tree-slide)

(defvar org-show-comments-state t)

(defun hide-org-comments ()
  (interactive)
  (let ((cloak (face-attribute 'default :background)))
    (set-face-attribute 'org-meta-line (selected-frame) :foreground cloak)
    (set-face-attribute 'org-block-begin-line (selected-frame) :foreground cloak)
    (set-face-attribute 'org-block-end-line (selected-frame) :foreground cloak))
  (setq org-show-comments-state nil))

(defun show-org-comments ()
  (interactive)
  (let ((uncloak (face-attribute 'default :foreground)))
    (set-face-attribute 'org-meta-line (selected-frame) :foreground uncloak)
    (set-face-attribute 'org-block-begin-line (selected-frame) :foreground uncloak)
    (set-face-attribute 'org-block-end-line (selected-frame) :foreground uncloak))
  (setq org-show-comments-state t))

(defun toggle-org-comments ()
  (interactive)
  (cond
   (org-show-comments-state (hide-org-comments))
   (t (show-org-comments))))

(add-hook 'org-tree-slide-mode-hook  'toggle-org-comments)

(define-key org-tree-slide-mode-map (kbd "<left>") 'org-tree-slide-move-previous-tree)
(define-key org-tree-slide-mode-map (kbd "<right>") 'org-tree-slide-move-next-tree)

What is #+C?