Y started a business by investing an amount of Rs. 45,000. After 3 months P joined him with a capital of Rs. 60,000. After another 6 months X joined them with a certain amount a, capital. At the end of the year, if X's share is Rs. 4000 out of a profit of Rs. 20,000, then the investment of X(in Rs.) is

A

75,000

B

90,000

C

1,00,000

D

65,000