Which of the following characters of $Nostoc$ resembles other prokaryotes?

The body organization of blue-green algae differs from other algae because...

Assertion: Gram-negative bacteria do not retain the stain when washed with alcohol.
Reason: The outer face of the outer membrane of Gram-negative bacteria contains lipopolysaccharides,a part of which is integrated into the membrane lipids.

Select the correct option from Column-$I$ and Column-$II$.

Column-$I$	Column-$II$
$(A)$ Halophiles	$(p)$ Gram-positive bacteria
$(B)$ Firmicutes	$(q)$ Hot springs habitat
$(C)$ Methanogens	$(r)$ Gram-negative bacteria
$(D)$ Spirochetes	$(s)$ Photosynthetic bacteria
$(E)$ Thermoacidophiles	$(t)$ Extremely salty areas
	$(u)$ Responsible for biogas production

In the five-kingdom classification,the kingdom that includes blue-green algae,nitrogen-fixing bacteria,and methanogenic archaebacteria is:

$A$ bacterium which is commonly present in the intestine of man and animal is