If you wish to collect data from two related websites with different domains in a single google analytics property, what feature must you set up?

The question has multiple choices

a) Advanced filters

b) Cross-domain tracking

c) Event tracking

d) Custom Dimensions

The answer is b) Cross-domain tracking

Sometimes called site linking, this feature makes it possible for Google analytics to see sessions on two related websites as a single session by a single user. To track these sessions, Google analytics collects Client-Id value stored in cookies. In the case of multiple domains, the Client-Id value has to be carried from one domain to another.