The dig command is a tool that can be used to query DNS servers and obtain information about domain names, such as IP addresses, mail servers, name servers, or other records. The MX option specifies that the query is for mail exchange records, which are records that indicate the mail servers responsible for accepting email messages for a domain. Therefore, the command dig company.com MX would best help the tester determine which cloud email provider the log-in page needs to mimic by showing the mail servers for company.com. For example, if the output shows something like company-com.mail.protection.outlook.com, then it means that company.com uses Microsoft Outlook as its cloud email provider. The other commands are not as useful for determining the cloud email provider. The whois command is a tool that can be used to query domain name registration information, such as the owner, registrar, or expiration date of a domain. The curl command is a tool that can be used to transfer data from or to a server using various protocols, such as HTTP, FTP, or SMTP. The dig command with the A option specifies that the query is for address records, which are records that map domain names to IP addresses.