Sir,
Of the three scenarios, only Taiwan required a direct military intervention because it directly goes against the CCP's tenets, ie the unification of China.
Korea is a hell of a lot more complex. The Chinese don't mind a united Korea under Seoul or even under Kim for that matter but they do need, I mean need, not want, but need the Americans to stabilize a united Korea.
The major fear for Beijing is that a untied Korea would easily, extremely easily, goto war with Japan, forcing China to choose sides ... and there is little doubt which side she would choose and it's not sipping sake in Tokyo.
Such a war would cripple NE Asian trade ... and therefore, China.
Given these two events, India rates an extreme third, especially when you consider what either side has to gain - a bunch of rocks.