Sorting on date basis

Shell Programming and Scripting
1

I have file data.txt having below data

cat data.txt

01-MAY-13 2.38.11.00.100089 IN 4512 0000741881
01-MAY-13 2.38.11.00.100089 IN 4512 0000741881
01-JUN-13 2.38.11.00.100089 FC 1514 0000764631
01-NOV-13 2.38.11.00.100089 FC 1514 0000856571
01-NOV-13 2.38.11.00.100089 IN 300.32 0000856531
01-MAY-13 2.38.11.00.100089 FC 4512 0000741881
01-JUL-13 2.38.19.00.100000 FC 2698 0000764493
01-NOV-13 2.38.19.00.100000 IN 2698 0000856493
01-JUL-13 2.38.19.00.100000 IN 2850.14 0000768996

sort -n -k a.txt

but it is not working

i want to sort the above data on first date basis (first column) and IN should be preference on FC and my output should be as below

cat data.txt

01-MAY-13 2.38.11.00.100089 IN 4512 0000741881
01-MAY-13 2.38.11.00.100089 IN 4512 0000741881
01-MAY-13 2.38.11.00.100089 FC 4512 0000741881
01-JUN-13 2.38.11.00.100089 FC 1514 0000764631
01-JUL-13 2.38.19.00.100000 IN 2850.14 0000768996
01-JUL-13 2.38.19.00.100000 FC 2698 0000764493
01-NOV-13 2.38.11.00.100089 IN 300.32 0000856531
01-NOV-13 2.38.11.00.100089 FC 1514 0000856571
01-NOV-13 2.38.19.00.100000 IN 2698 0000856493

Please help

Thanks in advance

2
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