How is the underlined pronoun used in the sentence?

((who)) at the park left a pair of mittens on the ground?

a.
subject

b.
direct object

c.
possessive

d.
object of a preposition

Ill give 50 points and brainiest if i can. would be grateful for any on this. the industrial revolution moved the united states into a new economic era. using the resources provided respond to the following prompts as they deal with economic development in the united states. using the maps available on the web links tab, explain the economic development of the united states, especially in regard to its emergence as a major industrial power. (focus on industrial sections; cities and towns; territorial growth; agricultural, mineral, and resource regions; coal fields; slavery; value and production; and distribution of agriculture and manufacturing areas.) using the available maps, explain the economic advantages of the physical geography of the united states. explain the gains that the united states made from trade.

What is hamlet pondering at the beginning of act 3?

Whatever crawls in is trapped. is the noun clause - whatever crawls? is the function of the noun clause the subject of the verb trapped?