This sentence describes a situation where contributions that were promised have not been fulfilled, causing delays in important projects. The phrase "are ___ delivered" suggests the need for a passive construction that fits with the present perfect tense or a structure that describes an expected action that hasn't happened yet.
Option (a): Grammatically, "just now" is an adverbial phrase typically used with the past tense to indicate something that happened a moment ago. Contextually, it implies that the deliveries have only recently occurred, which contradicts the idea that projects are delayed or abandoned due to undelivered contributions. This does not fit.
Option (b): Grammatically, "are yet to be delivered" is correct and follows a passive construction that implies the action has not happened but is expected. Contextually, this matches the idea that contributions have not been delivered, which is why projects are delayed or abandoned. This is both grammatically and contextually appropriate.
Option (c): Grammatically, this is incomplete. It would need a past participle after it: "already been delivered." Even if completed, saying contributions have "already been delivered" contradicts the cause of delays or abandonment. This is incorrect both grammatically and contextually.
Option (d): Grammatically incorrect. The subject "contributions" is plural, but "does" is singular. Also, "yet does not delivered" is structurally flawed. Contextually, it renders an incorrect meaning. This option is grammatically incorrect and contextually irrelevant.
Option (e): Grammatically, "are already delivered" is acceptable, but the meaning contradicts the following clause about delays and abandonment. Contextually, it suggests the contributions were made in time, which goes against the passage's message. Incorrect due to contextual mismatch.
Hence, option (b) is the answer.