Utilize the input text as a context reference, choose the right relationship between 'Ofcom' and 'postal sector' from the options.
Options: headquarters location, legal form, industry, product/material produced

Fri, Jul 17, 2015, 13:21 BST - UK Markets close in 3 hrs 9 mins Royal Mail shares drop as Ofcom launches ‘fundamental’ review of postal sector By Jon Yeomans | Telegraph – 46 minutes ago 512.50 -14.5000
industry