Answer:
The correct answer to the response given to the initial sentence: Lourdes y yo podemos ir a ayudarte esta tarde (no es seguro), would NOT be with puedamos, but with podamos. As such, the sentence should be: No es seguro que Lourdes y yo podamos ir a ayudarte esta tarde, which, from the answer choices at the last part, would make this an incorrect use of the word.
Explanation:
Podamos comes from the irregular verb poder, and it is considered a subjunctive in the present tense. Can only be used when the sentence starts with the first plural pronoun. Although in the sentence we have Lourdes and I, these two can be transfered to their pronoun We, and therefore, as per the Spanish rules of correct use, the verb must be used in its present subjunctive form, which is podamos, not puedamos.
