Which of these components is/are not present in Gram-negative bacteria?

The correct option is A Teichoic acid
Gram stain is used to stain bacteria. It was developed by Christian Gram in 1884. Chemically, gram stain is a weakly alkaline solution of crystal violet or gentian violet. Depending on the ability of the cell wall to stain with Gram stain, bacteria are grouped into two categories. The bacteria which retain colour even after washing with alcohol or acetone are gram positive and those who do not retain colour are gram-negative.

The Gram-positive bacteria have smooth, thick cell wall. The wall contains teichoic acid and 70-80% murein.

The Gram-negative bacteria have wavy, thin cell wall with outer membrane with hydrophilic channels. The wall contains 10-20% murein and 20-30% lipids without teichoic acid.

Option A is correct.