office 365

i have some questions , i dont need any explanation, i would appreciate if you can just provide me the correct answer , as i am confused by internet answers.

question 1:
A company plans to deploy an Office 365 tenant.

You have the following requirements:
Administrators must be able to access the Office 365 admin center.
Microsoft Exchange Online must be used as a Simple Mail Transfer Protocol (SMTP) relay for a line-of-business

application that sends email messages to remote domains.

for smtp relay -it gives 2 options , port 25 and port 587

some answers say 25 some say 587 , bit confused, which is the correct answer

Question 2

Your company has a hybrid deployment of Office 365. You need to create a group. The group must have the following

characteristics:
Group properties are synchronized automatically.
Group members have the ability to control which users can send email messages to the group.

A.Create a distribution group and configure the Mail Flow Settings.
B.Create a new role group.
C.Create a distribution group and configure the Membership Approval settings.

which one is correct

Question 3:

A company deploys an Office 365 tenant.

All employees in the human resources (HR) department must use multi-factor authentication. They must use only the

Microsoft Outlook client to access their email messages. User1 joins the HR department.

You need to help User1 configure his account.

answer is first enable multi factor authentication

getting confused here whether to instruct user to use phone to complete the regsutration process and then create app

password or instruct user to create app password to complete registration process

question no.4

All users report that they cannot access Exchange Online to check their email.

i need to use the Microsoft Remote Connectivity Analyzer and the credentials of the users.

for microsoft outlook for mac -should i use outlook connectivity or microsoft exchange web services connectivity test?