Nate learned that there has to be more to this question...
I think you would use all of them not for sure though. But if you only have one option I would use the name of the website or book
It should be "I will be" because this sentence is past tense. Meaning the "I will be" would be in the future. And since those are the answers 'I will be' would be the the answer. Which means the sentenced corrected would be: I was happy to help you in the garden when I came to visit you last month.