The term used by Kabir from Vedantic traditions to define the 'unseen' is:

Alakh

The correct answer is Option (4) → Alakh

Kabir’s poems have survived in several languages and dialects; and some are composed in the special language of nirguna poets, the sant bhasha. Others, known as ulatbansi (upside-down sayings), are written in a form in which everyday meanings are inverted. These hint at the difficulties of capturing the nature of the Ultimate Reality in words: expressions such as “the lotus which blooms without flower” or the “fire raging in the ocean” convey a sense of Kabir’s mystical experiences. Also striking is the range of traditions Kabir drew on to describe the Ultimate Reality. These include Islam: he described the Ultimate Reality as Allah, Khuda, Hazrat and Pir. He also used terms drawn from Vedantic traditions, alakh (the unseen), nirakar (formless), Brahman, Atman, etc. Other terms with mystical connotations such as shabda (sound) or shunya (emptiness) were drawn from yogic traditions.