You are trying to make the loving and the choosing two separate issues. Really they are the same.
What does it mean to love?
Romans 5:8 nkjv " But God demonstrates His own love toward us, in that while we were still sinners, Christ died for us. "
So the work of Christ, particularly his atoning death was his primary act of love.
What then is his election? Well election is a "choosing". What did he choose us for? Look at what Paul teaches in Ephesians 1.
Ephesians 1:4-6 4 just as He chose us in Him before the foundation of the world, that we should be holy and without blame before Him in love, 5 having predestined us to adoption as sons by Jesus Christ to Himself, according to the good pleasure of His will, 6 to the praise of the glory of His grace, by which He [a]made us accepted in the Beloved.
So we were chosen to be made Holy by the Son (Via the atoning death previously mentioned). The choosing in itself is the first expression of that love. A key doctrine of a calvinist/reformed understanding is that God did not choose us because of anything that we have done or will do. This is the "Unconditional" portion of the unconditional election.
this makes the Gospel of Grace truly by grace, and not by any merit of our own.
eph 2:8-9 For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, 9 not of works, lest anyone should boast.
So to be concise, we can clearly remove option "A" from your question. With option "B" being closer to the understanding. But really the answer is that God's choosing is just the initial expression of his loving, and not really separable. His choosing and his loving are one in the same.
The best consolation we are given as to why God chose is in the above verse from
ephesians 1:5(partial) "according to the good pleasure of His will"