Regarding online advertising payment models, the model puts all the risk on the advertiser, while the puts all the risk on the advertising platform.

Multiple Choice

pay$-$per$-$click; pay$-$per$-$impression

pay$-$per$-$click; pay$-$per$-$conversion

pay$-$per$-$conversion; pay$-$per$-$click

pay$-$per$-$impression; pay$-$per$-$click

pay$-$per$-$impression; pay$-$per$-$conversion