AppTrack: Tracks and reports applications passing through the device.
- Intrusion Detection and Prevention (IDP): Applies appropriate attack objects to applications running on nonstandard ports. Application identification improves IDP performance by narrowing the scope of attack signatures for applications without decoders.
- AppFW: Implements an application firewall using application-based rules.
- AppQoS: Provides quality-of-service (QoS) prioritization based on application awareness

B). IPS applies the most severe action to traffic matching multiple rules. When traffic matches more than one rule, the action taken will be the most severe one specified among the matching rules.
C). IPS evaluates rules sequentially. This means that the rules within an IPS policy are processed in a specific order, typically from top to bottom.

JIMS server is a Juniper Identity Management Service that collects user identity information from different authentication sources for SRX Series devices12. It can connect to SRX Series devices and CSO platform in your network1.
JIMS server is a service that protects corporate resources by authenticating and restricting user access based on roles2. It connects to SRX Series devices and CSO platform to provide identity information for firewall policies1. To reduce the load that JIMS server places on your network, you should connect JIMS to another SRX Series device1. This way, you can distribute the identity information among multiple SRX Series devices and reduce network traffic.

Explanation
The DNS ALG is an application layer gateway that handles data associated with locating and translating domain names into IP addresses.
The DNS ALG supports the following features:
DDNS: The DNS ALG supports dynamic DNS (DDNS), which allows hosts to update their DNS records dynamically when their IP addresses change.
The DNS ALG monitors the DDNS update messages and performs the necessary address transformations2 DNS doctoring: The DNS ALG performs DNS doctoring, which is a process of modifying the DNS responses to match the NAT address translation. This is done to resolve the problems introduced by NAT, such as the mismatch between the internal and external IP addresses of a host. The DNS ALG performs the IPv4 and IPv6 address transformations for both DNS and DDNS responses2 The DNS ALG does not support VPN tunnels or NAT itself. The DNS ALG works with NAT, but does not perform NAT. The DNS ALG only supports UDP traffic, not TCP traffic2 References:
1: Juniper Security Specialist (JNCIS-SEC) (JN0-334) | Study Guide 3
2: Junos OS Security Configuration Guide | DNS ALG 1