Assuming 8 bits for data, 1 bit for parity, I start bit and 2 stop bits, the number of characters that 1200 BPS communication line can transmit is.

First, we need to calculate the total number of bits per character.
We have:
- 8 data bits
- 1 parity bit
- 1 start bit
- 2 stop bits
So, the total bits per character = 8 + 1 + 1 + 2 = 12 bits.
Now, we know the communication line transmits at 1200 BPS (bits per second).
To find the number of characters per second (CPS), we divide the BPS by the bits per character:
CPS = 1200 BPS / 12 bits/character = 100 characters/second.
Therefore, the correct answer is 100 CPS. Option A is the correct answer.