For this unit Refers to Student’s Book pages Writing headlines

proposals 
(focusing on creative ideas within a fixed budget) or 
bids
 (cost-
based proposals, typically based on detailed requirements from the broadcaster) from 
those received from various production companies. Production companies may also be 
invited to 
pitch
 new ideas for programmes. Some broadcasters only accept proposals/
bids/pitches from approved production companies, in order to manage quality and 
avoid being overloaded with ideas for programmes.
Useful web links
The BBC site on commissioning contains a wealth of information 
http://www.bbc.co.uk/commissioning/
 
Information about commissioning programmes for Radio 4
http://www.bbc.co.uk/commissioning/radio/network/radio4.shtml