The correct option is B monocot root
Exarch is used when there is more than one strand of primary xylem in a stem or root, and the xylem develops from the outside to inwards, towards the center, i.e. centripetally. In monocot root, vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Exarch and polyarch vascular bundles occur in monocot root.