Application of Tara Guelig and Yuri Horwitz, as amended, pursuant to 11 DCMR Subtitle X, Chapter 9, for a special exception under Subtitle D § 5201 from the rear yard requirements of Subtitle D § 1206.3, to construct a rear addition to a one-family dwelling in the R-20 Zone at premises 2716 O Street N.W. (Square 1239, Lot 143).