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Hello,

IGMP is a communications protocol.  It is not a routing protocol.  You are also missing one correct answer which is  IGMP snooping runs on Layer 3 routers.  This is indeed correct.  See link

http://en.wikipedia.org/wiki/Internet_Gr...t_Protocol

25. (QID:NG16) Which three statements are true about the Internet Group Management Protocol (IGMP)? (Choose three)

IGMP is used to register individual hosts with a multicast group.
IGMP is a multicast routing protocol that makes packet-forwarding decisions independent of other routing protocols such as EIGRP.
IGMP version 3 enables a multicast receiving host to specify to the router which sources it should forward traffic from.
IGMP messages are IP datagrams with a protocol value of 2, destination address of 224.0.0.2, and a TTL value of 1.
There are three IGMP modes: dense mode, sparse mode, and sparse-dense mode.
IGMP snooping runs on Layer 3 routers.

Correct Answer:

IGMP is a multicast routing protocol that makes packet-forwarding decisions independent of other routing protocols such as EIGRP.
IGMP is used to register individual hosts with a multicast group.
IGMP version 3 enables a multicast receiving host to specify to the router which sources it should forward traffic from.

IGMP runs on routers; IGMP snooping runs on layer 2 switches.

http://www.ciscosystems.com/en/US/docs/switches/lan/catalyst4500/12.1/8aew/configuration/guide/multi.pdf

Ok the document you linked states specifically that:
IGMP (on a router) sends out periodic general IGMP queries.  Therefore it does operate on a layer 3 router.  That statement is true.  The statement that IGMP is a routing protocol is false.  It is a communications protocol.  It does not route traffic but instead it allows hosts to subscribe to multicasts by sending requests at Layer 2.

1. You have to select three correct answers - which is not possible if you omit the "multicast routing protocol" option. I think a routing protocol is also a communication protocol.

2. Sometimes you have to settle with minor differences. After all boss is always right, and Cisco is the boss here.