will
is
shall
none of these
Answer is Right!
Answer is Wrong!
The correct answer is “will”.
“Will” is the most common modal verb used to express certainty. It can be used to talk about future events that are certain to happen, or to make promises or offers.
In the sentence “I will certainly do it”, the speaker is using “will” to express certainty that they will do something. This could be because they have already made a promise to do it, or because they are very confident that they will be able to do it.
The other options are not as likely to be used to express certainty. “Is” is used to talk about things that are true or exist, and “shall” is used to make requests or give orders. “None of these” is not a valid answer, as it does not include any of the possible options.