Final answer:
The Uds. form of the verb pensar in the present tense is piensan.
Step-by-step explanation:
The Uds. form of the verb pensar in the present tense is piensan.
For example, in a sentence like 'Ellos piensan que el examen fue difícil' (They think that the exam was difficult), 'piensan' is used to match the plural subject 'ellos' (they).
Therefore, option A, Piensan, is the correct answer.
Learn more about Verb conjugation in Spanish