You want to enable the minimum Juniper ATP services on a branch SRX Series device. In this scenario, what are two requirements to accomplish this…

To enable Juniper Advanced Threat Prevention (ATP) Cloud services on an SRX Series device, an administrator must first have an account on the Juniper cloud portal. This is the central point for management and reporting. After creating the account, the SRX device must be enrolled with the cloud service. The standard and most direct method for this is to download an enrollment script from the cloud portal and execute it on the SRX device. This script automates the configuration of secure connectivity and registers the device with the administrator's cloud account, thereby activating the ATP services.

A. Install a basic Juniper ATP license on the branch device. The free tier of Juniper ATP Cloud, which provides minimum services, is the default and does not require the installation of a license key.
B. Configure the juniper-atp user account on the branch device. The enrollment process does not involve creating a local user account. Device authentication with the cloud is handled through certificates and tokens configured by the enrollment script.

1. Juniper ATP Cloud Administration Guide - Enrolling SRX Series Devices: This official guide states

"Before you can enroll your SRX Series device with Juniper ATP Cloud

you must have a Juniper ATP Cloud account." It then details the enrollment procedure: "You can enroll your SRX Series device using a registration script that you download from the Juniper ATP Cloud Web UI." This directly supports options C and D.

Source: Juniper Networks TechLibrary

"Juniper ATP Cloud Administration Guide"

Section: Enrolling SRX Series Devices.

URL: https://www.juniper.net/documentation/us/en/software/juniper-advanced-threat-prevention-cloud/juniper-advanced-threat-prevention-cloud/topics/topic-map/atp-cloud-srx-series-enrollment.html

2. Juniper ATP Cloud Licensing Overview: This document clarifies the licensing model

stating

"Juniper ATP Cloud has a free model and a premium model. The free model is the default and does not require a license." This confirms that installing a license (Option A) is not a requirement for minimum services.

Source: Juniper Networks TechLibrary

"Juniper ATP Cloud"

Section: Licensing Overview.

URL: https://www.juniper.net/documentation/us/en/software/juniper-advanced-threat-prevention-cloud/juniper-advanced-threat-prevention-cloud/topics/concept/atp-cloud-licenses-overview.html