Refer to the Exhibit.
— Exhibit –

— Exhibit —
You must configure two SRX devices to enable bidirectional communications between the two
networks shown in the exhibit. You have been allocated the 172.16.1.0/24 and 172.16.2.0/24
networks to use for this purpose.
Which configuration will accomplish this task?

A.
Use an IPsec VPN to connect the two networks and hide the addresses from the Internet.

B.
Using destination NAT, translate traffic destined to 172.16.1.0/24 to Site1’s addresses, and
translate traffic destined to 172.16.2.0/24 to Site2’s addresses.

C.
Using source NAT, translate traffic from Site1’s addresses to 172.16.1.0/24, and translate traffic
from Site2’s addresses to 172.16.2.0/24.

D.
Using static NAT, translate traffic destined to 172.16.1.0/24 to Site1’s addresses, and translate
traffic destined to 172.16.2.0/24 to Site2’s addresses.

Explanation:

To examine bidirectional communication you need multiple packet filters, one for each direction.
Reference :http://my.safaribooksonline.com/book/networking/junos/9781449381721/securitypolicy/troubleshooting_security_policy_and_traf