问题：

[单选]

You are a security administrator for your company. The company has one main office and five branch offices. Network administrators work in the main office and each branch office.   
Network administrators in the main office frequently create scripts that automate common 
administrative tasks. You review each script to ensure it does not introduce security vulnerabilities. Scripts that do not introduce security vulnerabilities are considered approved. Occasionally， branch office administrators modify these scripts and distribute the modified scripts to other 
branch office administrators. Branch office administrators often report that they accidentally run a modified version of a script.   
You need to ensure that branch office administrators can verify which scripts are approved scripts. 
What should you do？（）

A .  Maintain a list of the dates that the approved scripts were last modified. lnstruct branch office administrators to verif
B .  Digitally sign All approved scripts. Instruct branch office administrators to verify the signature before using a script.
C .  Distribute all approved scripts to branch office administrators in an e-mail message.
D .  Place all approved scripts on a file server in the main office. Assign All branch office administrators only the Allow -the approved scripts. Instruct administrators to copy scripts from this file server.