Read the following excerpt from a US court opinion:
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immunity from civil suit based on their testimony because without such immunity, "the truth-seeking process at trial would be impaired.” Id. at 1505. The Court reasoned in Rehberg that "[t]he factors that justify absolute immunity for trial witnesses apply with equal force to grand jury witnesses.” Id. Although here we deal with a different form of speech protection, we similarly hold that the factors justifying First Amendment protection against retaliation for trial witnesses apply with equal force to subpoenaed deposition witnesses. 4 . We note that, unlike the plaintiff in Huppert v. City of Pittsburg, 574 F.3d 696 (9th Cir. 2009), Karl is not a police officer whose duty under state law is to testify truthfully as part of her professional responsibilities. See 574 F.3d at 707-08  (internal quotation marks and brackets
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What is the most suitable continuation to the opinion? Your options are:
A. holding that a defendants false grand jury testimony was insufficient to establish perjury where the defendant was called before the grand jury for the mere purpose of laying the foundation for a perjury prosecution such testimony was immaterial to the grand jurys purpose
B. holding that where witness refused to take the oath and testify his grand jury testimony should not have been admitted because he was not subject to cross examination before the grand jury
C. recognizing that although no obstruction occurs when an individual lies to fbi agents who might or might not testify before a grand jury it may occur if the agents acted as an arm of the grand jury or indeed that the grand jury had even summoned the testimony of these particular agents
D. holding that under california law tjestifying before a grand jury charged with investigating corruption is one part of an officers job and therefore any speech huppert gave during his grand jury testimony was pursuant to his duties as a police officer
E. holding that right was available in grand jury proceedings
Reply with [A, B, C, D, E] only.