Answer:
2. they want greater control over the placement of ads.
Explanation:
In Sponsorship, an advertiser will trust a third party their brand. The advertiser can give suggestion on how the ads should be done, but the third party still have the freedom to either accept or reject the suggestion.
In participation, an adverser bought an alloyed amount of time in a specific platform (for example, a segment in a talk show). In that alloyed time, the advertiser have the full freedom to design their advertising process however they want. This made them able to have greater control over the placement of their ads.