Like many multiple choice questions, I don't really see the correct choice in the possible answers. I suppose I'd choose "I fell in love with Jesus', but even that doesn't give the whole picture of why I am a Christian. The real answer is that He came into my life so that I got to know Him.
It is kind of like the Peter story where you read about Jesus asking Peter if he love Him. Peter says he does love Him, but uses a different word for love. Jesus uses the word agape , meaning a very deep love, but Peter responds using the word phileo which might be better translated that Peter liked Jesus. Our English translations don't really give that section of Scripture a fair understanding, but getting to actually know Him does.
The Lord is incredible. He is awesome. It is hard for me to understand why He came into my life like He did. I am a Christian because He did come into me life and know we are friends. There are times when I do feel an even deeper love for Him, but that then to come a go a bit. There are even times when I find myself getting angry with Him. Things too often don't work out like I think they should and I know He can change that. There are those Job moments when you just feel He is letting the devil beat up on you and that can get a person angry at Him.
So I am a Christian because I know Jesus Christ personally. We are friends and I like Him. I also get zealous for Him. I find Him interesting and worth while talking to. Yet for me anyway, my relationship with Him seems to be like Peter's relationship with Him. Maybe others have a better relationship with Him, but so many who say they love Him hardly ever seem to actually seek Him for advice, instruction, and such, so do they or are they just saying they do? Maybe they do but just don't have time to actually spend with Him?
Anyway, I am a Christian because that I believe in Him in a way that makes Him my Lord! He came into my life so that I can hear from Him and so He gives me instructions, counsel, teachings, and does a multitude of things to help me. That answer is not an option in the OP, but it should be.
Romans 10:9,10 But what does it say? “THE WORD IS NEAR YOU, IN YOUR MOUTH AND IN YOUR HEART”—that is, the word of faith which we are preaching, that if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you will be saved;