In we have
Hence for the term independent of x,
30 – 3r = 0
i.e. r = 10
hence T11 has coefficient 15C10 210 ...(1)
and term with x15 will have 30 – 3r = 15
i.e. 15 = 3r
i.e. r = 5
∴ coefficient will be 15C5 25 ...(2)
∴ ratio of coefficient of x15 to the term independent of x will be
i.e. ratio will be 1 : 32
Hence, the correct answer is option B.