The correct answer a/b/c/d

Options

A. Both Assertion (A) and Reason (R ) are true and Reason ( R) is a correct explanation of Assertion (A).
B. Both Assertion (A) and Reason (R ) are true but Reason (R ) is not a correct explanation of Assertion (A).
C. Assertion (A) is true and Reason (R ) is false.
D. Assertion (A) is false and Reason (R ) is true.

Answer

A

Explanation

The Reason (R) is clearly true
Radius of each coin =` (1.75)/2 " cm , thickness " =2/(10) cm =1/5 cm `
`therefore` volume of each coin =`pir^2h=((22)/7xx(1.75)/2xx(1.75)/2xx1/5)cm^3`
`=((11)/(70)xx(175)/(100)xx(175)/(100))cm^3=(77)/(160) cm^3`
Volime of cuboid `=(10xx(55)/(10)xx(35)/10)cm^3=(385)/2cm^3`
Number of coins `=(385/2xx(160)/(77))=400`, which is true
Clearly , Reason (R) is true and Assereation (A) gives Reason (R)
So, the correct answer is (a)