Answer: Option A

Answer : Option A

Explanation :

$MF#%\sqrt{307} < 18$MF#%

Prime numbers < 18 are 2, 3, 5, 7, 11, 13, 17
307 is not divisible by 2
307 is not divisible by 3
307 is not divisible by 5
307 is not divisible by 7
307 is not divisible by 11
307 is not divisible by 13
307 is not divisible by 17
Hence 307 is a prime number

$MF#%\sqrt{437} < 21$MF#%

Prime numbers < 21 are 2, 3, 5, 7, 11, 13, 17, 19
437 is not divisible by 2
437 is not divisible by 3
437 is not divisible by 5
437 is not divisible by 7
437 is not divisible by 11
437 is not divisible by 13
437 is not divisible by 17
But 437 is divisible by 19 => 437 is not a prime number

$MF#%\sqrt{247} < 16$MF#%

Prime numbers < 16 are 2, 3, 5, 7, 11, 13
247 is not divisible by 2
247 is not divisible by 3
247 is not divisible by 5
247 is not divisible by 7
247 is not divisible by 11
But 247 is divisible by 13 => 247 is not a prime number

$MF#%\sqrt{203} < 15$MF#%

Prime numbers < 15 are 2, 3, 5, 7, 11, 13
203 is not divisible by 2
203 is not divisible by 3
203 is not divisible by 5
But 203 is divisible by 7 => 203 is not a prime number