compare and extract lines from multiple text files

Hi

I have three text files

A.txt

2016-09-12 11:10

2016-09-12 11:45

2016-11-26 21:53

2016-07-05 10:17

2016-17-26 01:53

B.txt

2017-04-28 2:19 1

2

3

2017-06-11 9:16 4

5

6

2016-11-26 21:53 7

8

9

2017-02-24 2:34 10

11

12

2016-07-05 10:17 13

14

15

and

C.txt

36.94 128.91 36.598 128.808 14.4 021920 CHYB 0.2 41.67 21.12 22

0.27581 0.3125 -0.18289 0.01911 -0.164 -0.12759 -0.29785 0.33008 -0.14826 0.03647

36.94 128.91 37.274 129.187 2.1 091653 CHYB 0.3 44.58 79.84 18

-0.15509 -0.33082 0.03158 -0.00179 0.22133 -0.08324 0.27631 0.00557 0.02958

36.22 127.97 36.344 127.336 5.4 215242 CPR2 0.2 58.73 25.78 6

-0.08287 0.03073 -0.02138 0.06548 0.26681 -0.25878

36.22 127.97 36.382 127.798 13.4 023438 CPR2 0.2 27.23 18.26 36

-0.16245 -0.03712 0.19955 -0.2824 -0.20541 -0.08394 0.11936 0.32622 0.29109 0.15924 0.01158

36.22 127.97 35.984 127.979 1.6 101730 CPR2 0.3 26.3 36.47 36

0.01215 -0.1267 -0.30525 -0.1333 0.1172 -0.40318 0.0829 0.132 0.39883 0.12017

First I want to compare A.txt with B.txt

If first two columns compared the I need to extract three rows starting from compared lines (Lines will be like 123, 456,789) column 3 in B.txt is only the line number which may be in different column if the line is blank. Multiple entries may be there in B.txt so, I need to keep it.

[Bob Thompson]

I'm not sure I understand all that your trying to do. Here is what I got:

1) Find the row number of dates in A that can be found in B.

2) Use the identified row numbers to get information from those rows in C.

Is this correct?