The symbiotic nitrogen-fixing bacteria present in root nodules of legumes belong to the genus

Bacteria found in root nodules of legumes are

Leghaemoglobin helps in

Arrange the stages of root nodule formation in the correct sequence:
$I-$ Infection thread is produced.
$II-$ Bacteria are carried to the cortex of the root.
$III-$ Bacteria attach to the root hair.
$IV-$ Bacteria are released from the thread into the cells.
$V-$ Differentiation into nitrogen-fixing cells occurs.

Which of the following plants does not have $Rhizobium$-containing root nodules?

Identify $A$ and $B$ in the figure.