In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: it takes 30 days to fill a laboratory dish with bacteria . if the size of the bacteria doubles each day , how long did it take for the bacteria to fill one sixteenth of the dish ? 
Options: a ) 16 days , b ) 26 days , c ) 27 days , d ) 28 days , e ) 29 days
b

Problem: average expenditure of a person for the first 3 days of a week is rs . 330 and for the next 4 days is rs . 420 . average expenditure of the man for the whole week is : 
Options: a ) 350 , b ) 370 , c ) 390 , d ) 430 , e ) none
b

Problem: if 4 xz + yw = 3 and xw + yz = 6 , what is the value of the expression ( 2 x + y ) ( 2 z + w ) ? 
Options: a ) 9 . , b ) 12 . , c ) 15 . , d ) 16 , e ) 18 .

c