Partnership solving puzzle

A starts a business with Rs.40,000/-. After 2 months B joined him with Rs. 60,000/-. C joined with them after some more time with Rs.1,20,000/-. At the end of the year out of total profit of 
Rs. 3,75,000/-, C gets Rs. 1,50,000 as his share.How many months after did B joined,did C join??

1) 4 months

2) 5 months

3) 6 months

4) 7 months 

Watch this space for answer in a week.