Fill in the blanks with the most appropriate option:-

I __________ this project by the time the new budget come out.

will have finished

The correct option to fill in the blanks is will have finished.

The sentence is about something that will be completed in the future, before the new budget comes out. The future perfect tense is used to describe actions that will be completed before a certain time in the future. It is the most appropriate tense to use in this context, as it describes the fact that the project will be completed by the time the new budget comes out.

The other options are not as appropriate:

• Would had finished is the past perfect conditional tense. It is used to describe actions that would have been completed in the past, if something else had happened. It is not as appropriate as "will have finished", as it does not convey the same sense of certainty or futurity.
• Shall have complete is the future perfect intransitive form. It is used to describe actions that will be completed in the future, but it does not specify a time or condition. It is not as appropriate as "will have finished", as it does not convey the same sense of specificity or accuracy.
• Should have complete is the past perfect intransitive form. It is used to describe actions that should have been completed in the past, but were not. It is not as appropriate as "will have finished", as it does not convey the same sense of futurity or certainty.