In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Q: Problem: a rower can row 5 km / h in still water . when the river is running at 2 km / h , it takes the rower 1 hour to row to big rock and back . how many kilometers is it to big rock ? 
Options: a ) 1.5 , b ) 1.8 , c ) 2.1 , d ) 2.4 , e ) 2.7

A: c
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Q: Problem: the speed of a boat in still water is 15 km / hr and the rate of the current is 3 km / hr . the distance travelled downstream in 12 minutes is 
Options: a ) 1.2 km , b ) 1.8 km , c ) 2.4 km , d ) 3.6 km , e ) none

A: d
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Q: Problem: a brick measures 20 cm * 10 cm * 7.5 cm how many bricks will be required for a wall 25 m * 2 m * 0.75 m ? 
Options: a ) 24000 , b ) 23000 , c ) 22000 , d ) 25000 , e ) 26000

A:
d
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