B. A hole in the ground will being dug by the boys
C. A hole in the ground can be dug by the boys
D. A hole in the ground is being dug by the boys
Explanation
This is a sentence of Past Continuous Tense.
Active sentences in the past continuous tense have the following structure: Subject + was/were + -ing form of the verb + object Passive sentences in the past continuous tense have the following structure: Object of the active sentence + was/were + being + past participle form of the verb + by + subject of the active sentence