You are taking a multiple-choice test that has 7 questions. Each of the questions has 5 choices, with one correct choice per question.

a)If you select one of these options per question and leave nothing blank, in how many ways can you answer the questions?

b) in a test of a gender-selection method, 14 babies are born and 10 of them are girls,

i) Find the number of different possible sequences of genders that are possible when 14 babies are box.
ii) How many ways can 10 girls and 4 boys be arranged in a sequence?