2. "Beyond the city of Gusu lies the Cold Mountain Temple, where the sound of the bell reaches the guest boats at midnight." On New Year's Eve, the abbot of Cold Mountain Temple strikes the bell 108 times, praying for peace in the world. It is known that there are two boats on the river outside the temple. When the first bell rings, the two boats start moving upstream and downstream at speeds of $3 \mathrm{~m} / \mathrm{s}$ and $9 \mathrm{~m} / \mathrm{s}$, respectively. If the distance from the temple to the riverbank is negligible, and the bell rings every $9 \mathrm{~s}$, with the speed of sound being $300 \mathrm{~m} / \mathrm{s}$, then when the passenger on the upstream boat hears the 108th bell, the passenger on the downstream boat has only heard ) bell rings.
(A) 107
(B) 106
(C) 105
(D) 104
2. D.

Let the upstream boat passenger hear the 108th bell at $t \mathrm{~s}$, at this time, the downstream boat passenger has only heard $x$ times. Then
$$
3 t=300(t-107 \times 9) \text {. }
$$

Solving for $t$ gives $t=107 \times \frac{100}{11}(\mathrm{~s})$.
Thus, the distance from the downstream boat to Hanshan Temple is $107 \times \frac{900}{11} \mathrm{~m}$.
Then $9 x+107 \times \frac{3}{11} \leqslant 107 \times \frac{100}{11}$
$$
<9(x+1)+107 \times \frac{3}{11} \text {, }
$$

which means $107 \times \frac{97}{99}-1<x \leqslant 107 \times \frac{97}{99}$.
Solving for $x$ gives $x=104$.