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 80s and 90s 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