Option 'c' is correct because penicillin is an anti biotic and an antibiotic when taken carefully helps us to get cured firm many diseases caused by bacteria because an antibiotic interferes in the biological pathway of bacteria to disturb it's metabolism and kills the bacteria and stops it from spreading a disease .

Introduction:
Penicillin is a widely used antibiotic drug that is effective in treating bacterial infections. It was the first antibiotic discovered and has been used for decades to combat a variety of bacterial illnesses. Penicillin works by interfering with the biological pathway of bacteria, ultimately leading to their death.

Interfering in the Biological Pathway of Bacteria:
Penicillin is classified as a bactericidal antibiotic, which means it directly kills bacteria rather than just inhibiting their growth. It targets the bacterial cell wall, which is crucial for maintaining the structural integrity of the bacteria. Penicillin disrupts the formation of the cell wall by inhibiting the enzyme responsible for cross-linking the peptidoglycan molecules in the bacterial cell wall. This weakens the cell wall, causing it to rupture and leading to the death of the bacteria.

Killing Bacteria:
As mentioned earlier, penicillin is a bactericidal antibiotic. It effectively kills a wide range of bacteria, including both Gram-positive and some Gram-negative bacteria. Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which makes them more susceptible to the action of penicillin. On the other hand, Gram-negative bacteria have an outer membrane that acts as a barrier, making them less susceptible to penicillin. However, some Gram-negative bacteria can still be targeted by certain types of penicillin or in combination with other drugs.

Both (a) and (b):
Given the aforementioned mechanism of action, penicillin can be categorized as a drug that both interferes in the biological pathway of bacteria and kills bacteria. By inhibiting the formation of the bacterial cell wall, penicillin disrupts the normal functioning of bacteria, ultimately leading to their death. Therefore, option (c) is the correct answer.

Conclusion:
Penicillin is a highly effective antibiotic drug that works by interfering in the biological pathway of bacteria and ultimately killing them. Its discovery and subsequent use revolutionized the field of medicine, providing a powerful tool for combating bacterial infections. However, it is important to note that penicillin is only effective against bacterial infections and has no effect on viral or fungal infections.