Which of the following groups would most concern the skyscraper issue

A．Skyscrapers provide more usable space than other buildings.
B．The skyscrapers first appeared in the late 1960's.
C．Where there are skyscrapers, television reception is poor.
D．The two World Trade Center towers are skyscrapers.

A．discuss the advantages and disadvantages of skyscrapers
B．compare skyscrapers with other modern structures
C．describe skyscrapers and their effect on the environment
D．illustrate various architectural designs of skyscrapers