Question: Which player has had more singles appearances, Casey Dellacqua or Olga Morozova? 
Sentence (from "Casey Dellacqua career statistics"): Dellacqua achieved a career high singles ranking of World No. 26 on September 29, 2014 and later achieved a career high doubles ranking of World No. 3 on February 1, 2016.
Relevant evidence: No