A. The paramMap is an object literal of the parameters in a route's URL path. The queryParamMap is an Observable of those same parameters.
B. The paramMap is an Observable that contains the parameter values that are part of a route's URL path. The queryParamMap is a method that takes in an array of keys and is used to find specific parameters in the paramMар.
C. paramMap is the legacy name from Angular 3. The new name is queryParamMap.
D. Both are Observables containing values from the requested route's URL string. The paramMap contains the parameter values that are in the URL path and the queryParamMap contains the URL query parameters.

Solution

D. Both are Observables containing values from the requested route's URL string. The paramMap contains the parameter values that are in the URL path and the queryParamMap contains the URL query parameters.