**Core Concept**
Putrefaction is a process of decomposition that occurs after death, characterized by the breakdown of tissue, leading to characteristic changes in color, odor, and texture. The greenish discoloration observed during putrefaction is due to the accumulation of certain compounds produced by bacterial action.

**Why the Correct Answer is Right**
The greenish discoloration in putrefaction is primarily caused by the production of sulfhemoglobin, a compound formed when sulfide ions react with hemoglobin. This reaction occurs in the presence of bacteria such as Clostridium welchii and Bacteroides fragilis, which are commonly found in the gut and other tissues. The sulfhemoglobin is responsible for the greenish color observed in the affected tissues.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the process of putrefaction or the production of sulfhemoglobin.
**Option B:** While bacteria are involved in putrefaction, the specific type of bacteria responsible for greenish discoloration is not mentioned.
**Option C:** This option is incorrect as it does not specify the correct mechanism or compound responsible for the greenish discoloration.

**Clinical Pearl / High-Yield Fact**
The greenish discoloration seen in putrefaction is a classic sign of decomposition and can be used to estimate the post-mortem interval (PMI). However, it is essential to note that the timing and extent of putrefaction can vary depending on factors such as temperature, humidity, and the presence of bacteria.

**Correct Answer: C.**