#26 please

4-26 Which collectors have the highest and the lowest maximum efficiency values, respectively? (a) Double-glazing, single-glazing (b) Single-glazing, double-glazing (c) Unglazed, single glazing (d) Single-glazing, unglazed (e) Double-glazing, unglazed 4-27 Which collectors have the highest efficiencies under practical operating conditions? (a) Single-glazing (6) Double-playing No-glacinia