What is the role of “huwa” in «جَاءَ زَيْدٌ وَهُوَ يَضْحَكُ»?

Supplementary Practice 2: Editing Rhetorical Expression, Context and Reasoning

• Turning wāw into a preposition
• Making the past verb subjunctive
• A subject pronoun referring to Zayd and forming a nominal circumstantial clause
• Identifying an unrelated new agent