math problems

2 L 2009
2 L 1004 .....1
2 L 502 ..... 0
2 L 251 ..... 0
2 L 125 ..... 1
2 L　62 ..... 1
2 L　31 ..... 0
2 L　15 ..... 1
2 L 　7 ..... 1
2 L 　3 ..... 1
2 L 　1 ..... 1
　　　1

So, 2009(10) = 11111011001(2)
(Remarks: Write the bottom "1" first, then write the "1" or "0" on the write form bottom to top.)
Ans: D

2.It is less troublesome than 1 because it has already told you how to write it.
2^0 + 2^1 + 2^3 + 2^9 + 2^10 +2^11
=1 + 10 + 1000 + 1000000000 + 10000000000 + 100000000000
= 111000001011

Ans: B

3. There maybe some problem in your question.
Fisrt, there is a "1" as the unit digit, so 2^0 must be included.
Hence, C is incorrect.

Then, we observe that there are 2 "1" in the first two digit, so there must be a term 2^k + 2^(k+1), where 2^(k+1) is the greatest power of 2.
Hence, B is incorrect.

But both A and D fulfill the above 2 requirement!

So, it cannot be determined. Had you make any typo? Or you miss something in the options?