Can you please go over this question? From Practice SAT 2005, Section 5, Question #27: “Paul ecke, flower grower and hybridizer, A. became B. known as “Mr. Poinsettia” after developing new varieties of the flower and C. by pioneering it D. as a living symbol of Christmas. E. No Error
I chose C (by pioneering) because I thought the “by” was a bit unnecessary to use (and I guess, unparallel as well).