【正确答案】 A

【答案解析】[解析] 题意：我们必须遵守规定。
划线词abide by意为：遵守；信守；承担……的后果。
A项stick to意为：坚持；粘住；忠于；信守；例：Obviously we are disappointed but the committee could do nothing less than stick to the rules.我们显然很失望，但委员会只能照章办事，别无他法。
B项persist in意为：坚持；固执于；例：If you persist in doing that you will end up in trouble.你要坚持做那件事的话，将来会有麻烦。
C项safeguard意为：保护，保卫；例：Safeguard your passwords and change them frequently.经常保护和更改你的密码。
D项apply意为：申请；涂，敷药；应用；例：The theory doesn"t apply.这理论不适用。故选A。