For this case the translation of the sentence in English is given by:
 It is essential that the indigenous communities ___________________ have their lands.
 Therefore, we must find the word to fill in the blank.
 The correct word is "can".
 Therefore, the complete sentence in English is:
 It is essential that the indigenous communities can have their lands.
 The translation of the sentence in Spanish is:
 Es indispensable que las comunidades indígenas puedan tener sus tierras.
 Answer:
 Es indispensable que las comunidades indígenas puedan tener sus tierras.
 D. puedan