Read this and answer the question

During the summers at Nohant, particularly in the years 1839–43, Chopin found quiet, productive days during which he composed many works, including his Polonaise in A-flat major, Op. 53. Among the visitors to Nohant were Delacroix and the mezzo-soprano Pauline Viardot, whom Chopin had advised on piano technique and composition. Delacroix gives an account of staying at Nohant in a letter of 7 June 1842:

Which of the two people that visited Chopin were tutored by him on piano?
Pauline Viardot