Data Sufficiency

Could someone please explain this?

it is D

Each term after second term is sum of two terms immediately preceding terms
=> K3=k2+k1
k4=k3+k2
k4=k2+k1+k2
k4=2k2+k1

//y k5=3k2+2k1

so the terms in the sequence can be generalized in the form of Kn=k2 + (n-3)(k2+k1)

=>K9=k2+6(k1+k2)
and K5=K2+2(k1+k2)


statement 1

K4=11
we know k5 and k4 (this is nothing but two different first degree equations with two unknowns) and hence we can find k1, K2 and thus k9

so statement 1 alone is sufficient

Statement 2
following the same logic as above we can find out k9

so statement 2 alone is sufficient


Hence the answer is D

IMO D
we have K5
1) given K4- we can find K6,K7 and so on
SUFFICIENT

2) given K6- using K5 and K6 we can find K7..and so on
SUFFICIENT