Which command on an EX Series switch allows for the configuration of the duplex setting on multiple interfaces at the same time?

A.
interface-range

B.
apply-path

C.
interface-group

D.
port-range

Explanation:
Interface-range:

The JUNOS Software allows you to group a range of identical interfaces into an interface range. You first specify the group of identical interfaces in the interface range.
Then you can apply a common configuration to the specified interface range, reducing the number of configuration statements required and saving time while producing a compact configuration.

Example: Interface Range Common Configuration

Configuration common to an interface range can be added as a part of the interface-range definition, as follows:

[edit]
interfaces {
+ interface-range foo {
+ member-range ge-1/0/0 to ge-4/0/40;
+ member ge-0/1/1;
+ member ge-5/[1-10]/*;
/*Common config is added as part of interface-range definition*/
mtu 256;
hold-time up 10;
ether-options {
flow-control;
speed {
100m;
}
802.3ad primary;
}
}
}

An interface-range definition having just member or member-range statements and no common configurations statements is valid.

These defined interface ranges can be used in other configuration hierarchies, in places where an interface node exists.