Solution : (1) Option (b) There was a school of fish in the pond.
Hint - In general, Collective noun is treated as singular. So here, "was" will be used with "school of fish".
(2) Option (b) He has a deck of cards.
Hint - The Collective noun for "cards" is "deck or peck".
(3) Option (c) A Crowd of people.
Hint - " Band" is the collective noun for a "group of musicians". "Troupe" is the collective noun for "group of dancers, actors". "Crowd" is a "group of people".
(4) Option (b) A Team of players.
Hint - "Crowd" is a "group of people". "Team" is a "group of players". "Band" is the "group of musicians".
(5)Option (c) A mob of angry protestors.
Hint - "Crowd" is a "group of people". "School" as a collective noun refers to a "group of fish". "Mob" refers to an "out of control group of people".
(6) Option (c) A class of students.
Hint - "Class" is a "group of people, generally used for students".
(7) Option(a) A gang of robbers.
Hint - "Gang" is a "group of criminals". "Crew" is a "group of people that work on ship". "Mob" refers to "an out of control group of people".
(8) Option(c) A choir of singers.
Hint - "Troupe" is a "group of dancers, actors". "Team" is a "group of players". "Choir" is a "group of singers".
(9) Option(b) A crew of sailors.
Hint - "Team" is a "group of players". "Crew" is a "group of people who work on ship". "Crowd" is a "group of people".
(10) Option(b) A litter of puppies.
Hint - "Flock" is a group of animals of one kind, specially sheep, goats or birds that are kept or fed together" . "Litter" is a "group of puppies" . "Swarm" is the collective noun for "Insects".