context: In London Chopin took lodgings at Dover Street, where the firm of Broadwood provided him with a grand piano. At his first engagement, on 15 May at Stafford House, the audience included Queen Victoria and Prince Albert. The Prince, who was himself a talented musician, moved close to the keyboard to view Chopin's technique. Broadwood also arranged concerts for him; among those attending were Thackeray and the singer Jenny Lind. Chopin was also sought after for piano lessons, for which he charged the high fee of one guinea (£1.05 in present British currency) per hour, and for private recitals for which the fee was 20 guineas. At a concert on 7 July he shared the platform with Viardot, who sang arrangements of some of his mazurkas to Spanish texts.
question: চপন যে বছর লন্ডনে ছিলেন সেই বছরের জুলাই মাসের ৭ তারিখে কে গান গেয়েছিল?
answers: Viardot