In DNA guanine is 10%. The content of adenine is
90%
80%
40%
20%
As discussed in Chargaff’s Rule -
If G=10% so, C will also be 10%
We know:
A + G = T + C
A + T + G + C = 100
A + T + 10 + 10 = 100
A + T = 100-20
A + T = 80
A = 40%; T = 40%
Hence, the correct option is (c).