Which is better option if I have to invest 5000/month, sip of 1000/-in 5 Mounds or sip of 5000/-in a single fund?

This depends on how many mutual funds you are holding. It does not make sense to invest in too many funds. About 5–6 should be good enough for most people. But as fund performances change, one can change the list over time. In your case given the smaller ticket sizes, about 2 to 3 separate funds would be an ideal solution.