Final answer:
Increasing media costs have resulted in advertisers preferring shorter commercials.
Step-by-step explanation:
From the information provided, the correct statement about commercial length is B. Increasing media costs have resulted in advertisers preferring shorter commercials.
As mentioned in the passage, conventional television advertising is on the decline due to technology allowing viewers to skip ads. This decline in advertising revenue prompts advertisers to prefer shorter commercials, as they are more cost-effective.
For example, advertisers can convey their message effectively in a 15-second spot while saving money on media costs compared to longer commercials.