Johnny and (i, me) are building the rocket for demonstration next month.

you need to post the passage so we know what you’re talking about

answer: b) bubbling its way

explanation: an adjective is a word or a group of words that modifies a noun (name, thing, place,

in this case, the first option "to heartily enjoy" isn't describing or modifying any noun, the third option "hiking along merrily" is describing an action but it doesn't modify any noun, the last option "beside us" is just a preposition that indicates position, so the correct answer is the second one: "bubbling its way" because it is modifying the noun "stream".