Marketers have been dealing with data for many decades now. According to the Expert Viewpoint conversation, the major difference between the key challenge marketers faced in the $80$s and $90$s vs what they face today is best characterized as: $($select all that apply$)$

Group of answer choices

linking databases from multiple sources vs$.$ reconciling real$-$time data from multiple sources and deriving insights

The data is more complex; not all the data is of good quality

The data is generated constantly; the velocity at which we receive data is high

The challenges have not changed much