If you wish to work in C,then,I would suggest libpq.I would wait for more replies on this,as I have little knowledge
about psqlODBC.
Thanks for the comments. Yes objective is to work in C and found libpq useful but am not sure about psqlODBC.
It would be really great to get comments from community here regarding comparison between both of them and also performance perspective. Based on my reading so far libpq is good from performance perspective.