Proxy_cache_methods and OPTIONS (1 reply)

I have bounced around quite a lot through forums and documentation to demistique whether the OPTIONS request method is honoured/allowed by nginx when it's configured as reverse proxy cache system or not.
I used a test box with nginx 1.4.6 with

"proxy_cache_methods GET OPTIONS;"

to test certain use case for a client but, reloading nginx returned obvious exception that:

"invalid value "OPTIONS" in /etc/nginx/sites-enabled/default:35"

Documentation says:
=============================================
Syntax: proxy_cache_methods GET | HEAD | POST ...;
Default:

proxy_cache_methods GET HEAD;

Context: http, server, location
=============================================

but I dont' see 1. full list and 2. list of allowed methods when proxy_cache is configured - if it makes the difference.

Anyu thoughts?