Refer to plain training, inc. if clients (the business owners) were asking for workshops to allow their customers to listen to audio files about their product or service, plain training would be organizing workshops.

The subject is related to a company called Plain Training Inc. which  helps people starting their own business; the multiple choices of answers are: 1.podcast, 2.blog, 3.forum, 4.social content site and 5.social game,

from which the most suitable answer is the 4th one, so Plain Training would be organizing "social content site" workshops, in order to boost their client's enthusiasm for advanced advertising and advance promotion techniques.

1. podcast

Explanation:

A podcast is a series of audio digital files made available on the internet for subscribers who can download to their computers or stream online.

From the example, it is noted that the clients(business owners) specifically asked for audio files(not videos) for their employees which fits exactly into a podcast workshop. Plain training would therefore make their audio files(podcasts) available to these clients.

the answer your looking for is c. : )

answer; biological;