The correct option is D to open
The correct answer here is Option D) - 'To Open'. This is because this phrase satisfies the rules of proper grammatical convention the best and follows the tense of the sentence as well (in this case, primarily present). The answer is to open as we use the infinitive form of the verb (to + root verb) when one verb is already conjugated ('managed'). Thus, to open is the correct answer. All other options are incorrect.