What is the last name of the person that Rose decided they should study at the Hoch Conservatory in Frankfurt, Germany?
Except for three months' formal schooling as a 12-year-old, during which he was bullied and ridiculed by his classmates, Percy was educated at home.  Rose, an autodidact with a dominating presence, supervised his music and literature studies and engaged other tutors for languages, art and drama. From his earliest lessons, Percy developed a lifelong fascination with Nordic culture; writing late in life, he said that the Icelandic Saga of Grettir the Strong was "the strongest single artistic influence on my life". As well as showing precocious musical talents, he displayed considerable early gifts as an artist, to the extent that his tutors thought his future might lie in art rather than music. At the age of 10 he began studying piano under Louis Pabst, a German immigrant then considered to be Melbourne's leading piano teacher. Grainger's first known composition, "A Birthday Gift to Mother", is dated 1893. Pabst arranged Grainger's first public concert appearances, at Melbourne's Masonic Hall in July and September 1894. The boy played works by Bach, Beethoven, Schumann and Scarlatti, and was warmly complimented in the Melbourne press.After Pabst returned to Europe in the autumn of 1894, Grainger's new piano tutor, Adelaide Burkitt, arranged for his appearances at a series of concerts in October 1894, at Melbourne's Royal Exhibition Building. The size of this enormous venue horrified the young pianist; nevertheless, his performance delighted the Melbourne critics, who dubbed him "the flaxen-haired phenomenon who plays like a master". This public acclaim helped Rose to decide that her son should continue his studies at  the Hoch Conservatory in Frankfurt, Germany, an institution recommended by William Laver, head of piano studies at Melbourne's Conservatorium of music. Financial assistance was secured through a fund-raising benefit concert in Melbourne and a final recital in Adelaide, after which mother and son left Australia for Europe on 29 May 1895. Although Grainger never returned permanently to Australia, he maintained considerable patriotic feelings for his native land, and was proud of his Australian heritage.
Grainger