Final answer:
The correct word to complete the sentence about the bond of the special forces soldiers remaining even after disbandment is 'solvent'.
Step-by-step explanation:
The word that best fits blank (1) in the sentence "Very few groups of coworkers bond as deeply as soldiers in a battlefield, so it was no surprise that the disbanded unit of special forces soldiers remained (1) even after it had been officially designated defunct." is C) solvent. The context suggests that the soldiers maintained their close relationship or coherence as a group, which would be an abstract use of 'solvent,' commonly known for its literal meaning pertaining to substances but sometimes metaphorically referring to a group that remains intact. Options A) tackle, B) extradite, and D) furtive do not fit contextually.