Fill in the blank with the most suitable word.

We won an unprecedented pardon from ________-President Karzai, and Gulnaz was freed.

then

The most suitable word to fill in the blank is then.

The sentence is about the time when the pardon was won from then-President Karzai. The word "then" is the most appropriate word to use in this context, as it refers to the specific time when the pardon was won.

The other options are not as appropriate:

• Those refers to people or things that have been mentioned previously. It would not be accurate to use "those" in this context, as the pardon was won from a specific person, not a group of people.
• At time is a prepositional phrase that means "during a particular time". It would not be accurate to use "at time" in this context, as it does not refer to a specific time.
• Later refers to a time that is after the present time. It would not be accurate to use "later" in this context, as the pardon was won at a specific time, not after the present time.