Task: Question Answering
Input (English): Problem: a man purchased earphone on friday. but he forgot how much it cost. the data he have are mean expenditure of all 7 days is 500. expenditure on mon, tue, wed, thurs, sat, sun are 450600, 400500, 550300. on friday he purchased 3 things one earphone, one pen and one notebook. pen cost 30 and notebook cost 50. then what is cost of earphone ?
Options: a. 620, b. 530, c. 450, d. 470, e. 500
Output (English): a