Can you check my answers?

Question

1.Which of the following shows the best next step to prove the following by mathematical induction?

3^n>n*2^n, n≥1
1.When n=1, the formula is valid because

3^1 1*2^1
3>2
2.Assuming that
3^k>k*2^k

a.3^k+1>k+1*2^k+1
b.3^k+1>k*2^k+1
c.4^k>k*3^k
d.3^k+1>(k+1)2^k+1

answer: A

Answer 1

correct, if you use a few parentheses:

3^(k+1) > (k+1)*2^(k+1)