Which sentence should be revised to include commas to set off a nonrestrictive element?

In B, “which we watch together” can be treated as extra information about the TV show, rather than information needed to identify it. Set that nonrestrictive clause off with commas: “The TV show, which we watch together, airs on Friday nights.” The clauses in C use “that” to identify which game, so they are restrictive and do not take commas.

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