Bolsa thinks they should find . William's grave William's aunt's grave William's parents' graves

The correct option that fills the blank in the sentence is:

Sancho and Bolsa.

In scene 7, Sancho and Bolsa interrogate Henrietta, asking her what William was like at work, after which, at the end of the scene, it occurs to Henrietta that William may be in the cemetery. Later, in scene 8, despite Sancho's refusals, Bolsa mentions the following:

"Let's get to his parents' graves, maybe if we're lucky he'll be visiting them and the case will be over."

Where it is appreciated that Bolsa was looking for the grave of William's parents, as a means of finding William.

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William's parents' graves

Explanation: