Salvavidas: señor, por favor. sr. garcía: está bien. nade cerca de la costa. usa bloqueador solar. nada con otras personas. usa gafas de sol.

The correct answer is:  [A]:  "Nade cerca de la costa."

Explanation:

This is a short dialog.

Note:

Given:

"Salvavidas:  Señor, por favor. ___(blank) " .

"Sr. García:  Está bien. "

    →  "Among the answer choices provided, choose the best answer choice /phrase/ that belongs in the blank."

The correct answer is:  [A]:   "Nade cerca de la costa."

Note:


"Salvavidas:  Señor, por favor.    Nade cerca de la costa  " .

"Sr. García:  Está bien. "

Explanation:


The dialog begins with a "lifeguard" speaking.  We know this because the "lifeguard" is identified by "occupation" rather than actual name; that is, the lifeguard is referred to as:  "Salvavidas"; which is the Spanish word for "lifeguard".  

The lifeguard begins this short dialog by saying,
 
"Sir, please.  ___( followed by a phrase from which we are to choose among the answer choices)___.

Then, "Sr. García" {"Mr. García"} responds by saying:  

"Está bien."  (which, in this context, is Spanish for:  "Okay." ;  or,  "All right." 

The answer choices provided are:

Choice:  [A]:  "Nade cerca de la costa."
                          →  "Swim near the coast."


Choice:  [B]:  "Usa bloqueador solar."  → "[It /he] uses sunblock."

Choice:  [C]:  "Nada con otras personas."  

                       → "[It /he] swims / [is swimming] with other people.

Choice:  [D]:  "Usa gafas de sol."  → "[It /he] uses sunglasses." 

Note:


→  The only answer choice that makes sense is:

→  Answer choice:  [A]:  "Nade cerca de la costa."

                          →  "Swim near the coast."

→  Furthermore, this "conjugation";  that is, "Nade" ; is a "command form" ; of the Spanish verb, "nadar" — which means:  "to swim" — that corresponds with the "Ud." {that is, "usted"} pronoun → which is the Spanish subject pronoun for the third person, single, [formal use of the word:  "you" ; when addressing or referring to ONE person] .

Since this is "lifeguard" initiating the conversation—in a "formal tone":

→  [e.g. "Señor, por favor.  " ; 

→  and from the [aforementioned] translations of all the other answer choices provided;  and that "Answer choice:  [A]" is the only choice with a "command form" conjugation; and phrase that makes sense;  and correct and appropriate "command form" — and text consistent with the context of the conversation; 

→  We determine that the correct answer is: 

Answer choice:  [A]:  "Nade cerca de la costa."

Ernesto (él) va a ir al comedor después de la sala.