<u>We took a kayak to a beach where sea turtles hatch.</u>
Explanation:
A restrictive clause is an adjective clause that provides essential information about nouns, meaning that they can not be taken out of a sentence without changing the sentence's meaning. Unlike nonrestrictive clauses, which provide extra information and are to be separated by commas, restrictive clauses are not separated by commas or any other type of punctuation.
In contrast to all the other sentences, sentence A is the one that contains a restrictive clause, which is “where sea turtles hatch.” This clause provides essential information about the noun “a beach” and is not set off by commas.