Reading operation from an LCD involves certain changes in the software, and the correct answer is option 'C' which states that both a low to high pulse at the E pin and setting the R/W pin high are introduced.

The software changes introduced for reading operation from an LCD are as follows:

1. **Low to high pulse at E pin:** The Enable (E) pin of the LCD is used to initiate data transfer and command execution. To read data from the LCD, a specific sequence of signals is required. The E pin is first set to a low logic level, and then a low to high pulse is applied to the E pin. This pulse triggers the LCD to output the data stored in the display RAM or the status information. By toggling the E pin, the LCD indicates that it is ready to transfer data.

2. **R/W pin set high:** The Read/Write (R/W) pin of the LCD determines the direction of data transfer. When the R/W pin is set high, the LCD is put into read mode. This allows the microcontroller or any external device to read the data stored in the LCD's display RAM or the status information. By setting the R/W pin high, the LCD acknowledges that it is ready to transmit data to the microcontroller.

By combining these two software changes, the microcontroller can read the data stored in the LCD's display RAM or obtain status information from the LCD. The low to high pulse at the E pin initiates the data transfer, and the R/W pin set high enables the LCD to transmit the desired data to the microcontroller.

To summarize, when performing a reading operation from an LCD, both a low to high pulse at the E pin and setting the R/W pin high are introduced in the software. These changes allow the microcontroller to read the data stored in the LCD's display RAM or obtain status information from the LCD.