John is a system administrator for a renowned travel agency.The agency is planning to upgrade its computer systems to Windows XP Professional.Most of the computers are networked but some computers do not have CD-ROM drives.How can John upgrade the computer systems without CD-ROM drives to Windows XP Professional?

• can attach a portable tape backup unit to each computer and install the operating system from it.
• can use the windows installer program to push out the operating system.
• can perfom the installation over a network share.
• can not install windows XP Professional unless he installs a CD-ROM drive in the computer systems that do not have them.