In spanish when you use a negative word after a verb, you need to add before the verb

nada

tampoco

no

nunca

If we want to make a negative sentence in Spanish, we need to use the word NO before the verb. 
e.g: ella no va a ir a la fiesta. (she is not going to the party). 
- Nada: means nothing. so you might say.  "no me pasa nada"
- tampoco: " yo tampoco voy a la fiesta (me neither) 
- Nunca: el nunca hace la tarea. (he never does his hw)

The only change would be to add the accent on esta (on the a) in esta in number 15.

Dis the correct answer