Which of the following is the property of B+ tree?

Each node has the maximum of M children and a minimum of M/2 children or any number from 2 to the maximum.

Each node has one fewer keys than children with the maximum of M -1 keys.

Keys are arranged in a defined order within the node.

All the leaves are on the same level, i.e. there is no empty sub tree above the level of the leaves.

All the leaves have been connected to form the linked list of the keys in a sequential order.