What is the mean of the underlined metaphor sentence the big job was not was not yet finished but nethan could see the light at the end of the tunnel

the correct answer is the last option

hope this

your pal abigail

imparadis't in one anothers arms  

the happier eden, shall enjoy their fill  

of bliss on bliss, while i to hell am thrust,  

where neither joy nor love, but fierce desire,  

among our other torments not the least,  

still unfulfill'd with pain of longing pines;  

yet let me not forget what i have gain'd  

from their own mouths; all is not theirs it seems:  

one fatal tree there stands of knowledge call'd,  

forbidden them to taste: knowledge forbidd'n?  

suspicious, reasonless. why should their lord  

envie them that? can it be sin to know,

i think the answer would mist likely be an adjective clause, because unhappy is an adjective.