Recordar in El Pretérito Imperfecto

Recordaba would be correct if they asked for "you" usted (formal). But,  the question was specific to  "you"  Tú (informal.) 

The spanish given was "Después del golpe, no  <select>  nada." , where one had to select for a list of answers.  There is nothing in above spanish that appears to indicate that the statement is addressed to an aquientance vs. stranger in a formal situation. How can one tell the correct conjugation is for "Tú"?  Is there maybe an informal rule of some sort I missed?

Hi Steve,

You are right. There is nothing telling you whether you need the informal or formal form. I added this to the hint: "Conjugate the "tú" form of "recordar" in El Pretérito Imperfecto.", so it is clear now which one we are asking for. 

Gracias y un saludo,

Inma