Option 1 -> "Rejoice" means to feel or show great joy, which is the opposite emotional expression to lamenting (expressing sorrow).
Option 2 -> "Approve" means to accept or agree with something, which doesn't directly oppose the emotional nature of lamenting.
Option 3 -> "Commiserate" means to express sympathy or share in sorrow, making it similar to lament rather than opposite.
Option 4 -> "Abate" means to decrease or diminish in intensity, which doesn't relate to the emotional expression of grief.
Hence, Option 1: rejoice -> "Lament" expresses sorrow and grief, while "rejoice" expresses joy and celebration, making them perfect antonyms in terms of emotional expression -> correct