Choose the correct word from the given options to complete the senten…

The correct answer is Option (2) → Although

Complete sentence: Although she was tired, she continued to work late into the night. Being tired would normally make a person stop, yet she kept working. The first clause is a concession, so "Although she was tired" is needed.

Option	Meaning and use	Example
(1) However	However is a conjunctive adverb, not a conjunction. It cannot join two clauses into one sentence with only a comma. The idea needs two sentences: "She was tired. However, she continued to work." Placed before "she was tired", it would mean "in whatever way", which makes no sense.	The road was narrow; however, the driver went on carefully.
(2) Although (answer)	Although (like "though" and "even though") is a subordinating conjunction: it joins a dependent clause to the main clause. It shows that the main action happens in spite of what the dependent clause says.	Although it was raining, the match went on.
(3) Unless	Unless means "if not" and states a condition. "Unless she was tired, she continued to work" makes no sense.	You will miss the bus unless you hurry.
(4) While	While mainly shows time (during the time that) or a contrast between two facts (whereas). It is sometimes used for concession in formal English, but "While she was tired" is first read as time. Although states the concession plainly.	She hummed a song while she cooked.

Contrast: although joins a clause of concession to the main clause. However links two separate sentences.