Which phrase best completes this conversation? laura: ¿qué precaución debo tomar si quiero nadar en el mar? salvavidas: nade lejos de la costa. es importante que no es necesario que no es recomendable que es preciso que

The right answer is the C) No es recomendable que.  

Explanation: Just to elaborate a little on the answer, it can be added that Laura is asking "what precaution must I take if I want to swim in the ocean?" The lifeguard will not likely say that "it is important that you swim far away from the shore" (option A) or that "it is essential that you swim far away from the shore" (option D). In addition, he/she will not likely say that "it is not necessary that you swim far away from the shore." The phrase that best completes the conversation is, therefore, the C: "It is not advisable that you swim far away from the shore."

lack of land area is one of the things not mentioned that has contributed to the poor transportation and communication systems in nicaragua.