Sadie aka Sarah, Millie and Annie McMillan, daughters of Rev John McMillan and Elizabeth Wiswell McMillan of Halifax. 

Annie Wiswell McMillan married William M Preedy of Halifax on the 3rd of September 1913 in Halifax, NS.

As per birth dates taken from the Halifax County 1891 Census, the girls may be Sadie sitting on the settee born 1871, Millie standing beside born 1872 and Annie sitting on the floor in front born 1874.