Need help with 19 to 21 with pitcure​

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.

Choose the sentence that accurately expresses a hurt back. me duele la mano. me duele la espalda. me duele el cuello. me duele el brazo.

Esta piña es mi piña. correct incorrect