Need plz i hope you can perfectly see the picture

The answer is a).

When doing estimation you put it to the nearest number. 24--> 25
21-->20.

The common multiple of 25 and 20 is 100 (25*4=100 and 20*5=100) and now you have found the common denominator. So you would do 17*4= 68 and 13*5=65
68+65=133

133 on 100 is obviously greater than 1.

B) 9*4=36 and 10*5=50 36+50=86
86 on 100 is not a greater sum than 1.

C) 12*4=48 and 9*5=45
48+45=93
93 on 100 is not a greater sum than 1.

I'll let you do D) so you can practice :)

Have a nice day/night and I hope I've helped you out!

~Soringthroughthesky