To find C's share of the annual profit, we'll first calculate the individual contributions of A, B, and C based on their investment durations.

Let's assume A's initial investment is "x" Tk. Since B invests double the amount after 6 months, B's investment at the beginning was "2x" Tk, and C invests thrice the amount after 8 months, so C's investment at the beginning was "3x" Tk.

Now, we need to consider the time each partner's money is invested:

A's money is invested for 12 months (the whole year).
B's money is invested for 6 months (half a year).
C's money is invested for 4 months (12 months - 8 months).
Now, let's calculate their shares of the profit based on their investments:

A's share = (A's investment duration / Total investment duration) * Total profit A's share = (12 / 12) * 27,000 = 27,000 Tk

B's share = (B's investment duration / Total investment duration) * Total profit B's share = (6 / 12) * 27,000 = 13,500 Tk

C's share = (C's investment duration / Total investment duration) * Total profit C's share = (4 / 12) * 27,000 = 9,000 Tk

So, C's share of the annual profit is Tk. 9,000.