Final answer:
Police can legally start interrogating a suspect after informing them of their right to remain silent and their right to an attorney, as required by the Miranda v. Arizona decision. Option B is correct.
Step-by-step explanation:
Police can legally begin their interrogation of a suspect after the suspect has been warned that his or her words can be used as evidence (option B). This is in accordance with the Supreme Court's decision in Miranda v. Arizona, which established that suspects must be informed of their right to remain silent and their right to an attorney before any police interrogation can legally proceed.
If a suspect chooses to answer questions without an attorney, they must also be informed that they can stop answering at any time until they talk to an attorney. This protocol is to ensure that a suspect's rights under the Fifth Amendment, which protects against self-incrimination and guarantees the right to due process, are upheld.