Is the noun engines a concrete or abstract

Hi how are i have some questions about english subject can you answer for me ?

The empire state building was a.constructed by one hundred workers. b.was first lit up by president roosevelt. c.has more than one hundred stories. d took several years to complete.

Which is most engaging way of describe how to conduct an interview? a. one of the most common mistakes of interviewers is to ask "force-choice" or "leading" questions. b. although one might be inclined following a script slavishly, one should react to the interviewee's answers. c. remember, you want to encourage the interviewee to talk. avoid asking simple "yes or no" questions. d. the person you are interviewing may provide a number of challenges that can be overcome with care.