The rock inscription recording the achievements of the Shaka ruler Rudradaman, which also mentions about the Sudarshan Lake is written in which language?

Sanskrit

In Girnar the Sudarshana Lake, an artificial reservoir is situated.  It is known from a rock inscription dating back to the second century CE, written in Sanskrit. The inscription credits the construction of the lake, complete with embankments and water channels, to a local governor during the Mauryan rule. The inscription also mentions the achievements of the Shaka ruler -Rudradaman.

Unfortunately, a devastating storm caused the embankments to breach, resulting in the water gushing out of the lake. At that time, Rudradaman, the Shaka ruler in the region, took responsibility for repairing the lake at his own expense without burdening his subjects with any taxes.

Interestingly, another inscription on the same rock, from the fifth century, mentions how one of the rulers of the Gupta dynasty once again undertook the task of repairing the Sudarshana lake.