Ignore this I'm very confused

Which one of the following is a trick used in spanish to identify the right hand? touch the tips of your index fingers with the tips of your thumbs. the hand that forms a lowercase b is your mano derecha. touch the tips of your index fingers with the tips of your thumbs. the hand that forms a lowercase d is your mano izquierda. touch the tips of your index fingers with the tips of your thumbs. the hand that forms a lowercase d is your mano derecha.

Yo te anoche. o a. llamo o b. llamaste o c. llamé o d . llamaron

Enuncia un ejemplo (sea social o natural) en el que creas se puede aplicar el cálculo y argumenta el tipo de proceso que es necesario para modelar tu ejemplo.