Gram negative bacteria are included under

Answer: Option B

Gram negative bacteria are included under Gracilicutes.
It is a gram-negative clade that branched off from other bacteria just before the evolutionary loss of the outer membrane or capsule, and just after the evolution of flagella.
The gram-negative bacteria include the model organism Escherichia coli, as well as many pathogenic bacteria, such as Pseudomonas aeruginosa, Chlamydia trachomatis, and Yersinia pestis.