The correct answer is option B: i and iii.
Explanation:
- A line printer prints an entire line at a time, which means it prints all the characters in a line simultaneously.
- It allows multiple copies to be taken at a time, which means it can print multiple copies of the same line without having to print each copy separately.
- However, a line printer is an impact printer, not a non-impact printer. Impact printers use a mechanism that physically strikes an inked ribbon against the paper to create an image, whereas non-impact printers use methods like heat or lasers to transfer the image onto the paper.
- Lastly, a line printer does not print one character at a time. It prints an entire line, not individual characters.
To summarize, a line printer prints an entire line at a time and allows multiple copies to be taken at once. Therefore, the correct answer is option B: i and iii.

A line printer is a type of printer that prints an entire line at a time. It is commonly used in environments where high-speed printing is required, such as businesses or large-scale data processing centers.

I. Prints an entire line at a time
A line printer is designed to print an entire line of text or characters in one go. It consists of a print head that moves horizontally across the width of the paper, printing one line of text at a time. This allows for fast printing speeds as the entire line is printed simultaneously, rather than printing one character at a time.

II. Non-impact printer
A line printer is a non-impact printer, which means it does not physically strike the paper to create an impression. Instead, it uses other methods such as inkjet, laser, or thermal printing to transfer the ink onto the paper. This results in quieter operation compared to impact printers, which use mechanisms like typewriters or dot matrix printers that strike the paper to create characters.

III. Allows multiple copies to be taken at a time
Line printers are capable of producing multiple copies of a document simultaneously. This is achieved by using carbon paper or carbon ribbon in conjunction with the original document. When the print head passes over the carbon paper or carbon ribbon, the ink is transferred onto additional sheets of paper, creating multiple copies of the original document.

IV. Prints one character at a time
The statement that a line printer prints one character at a time is incorrect. As mentioned earlier, a line printer prints an entire line at a time, not individual characters. This is what distinguishes a line printer from other types of printers, such as dot matrix printers or inkjet printers, which print one character or dot at a time.

To summarize, a line printer prints an entire line at a time, is a non-impact printer, and allows multiple copies to be taken simultaneously. However, it does not print one character at a time. Therefore, the correct answer is option B (i and iii).