Which sentence is correctly constructed with two clauses?
a. They passed the farm seeing a tethered goat with a bright orange stripe across its back.
b. They saw a tethered goat with a bright orange stripe across its back as they passed the farm.
c. Passing the farm, a tethered goat with a bright orange stripe across its back was seen.
d. A tethered goat with a bright orange stripe across its back was seen while passing the farm.