Answer:
Option c. 0.50
Explanation:
Simona's music book includes piano tunes = 50
by Bach = 7
by Mozart = 18
Total = 7 + 18 = 25
Probability of choosing a tune that it is either by Bach or by Mozart is
=
=

= 0.50
The probability that it is either by Bach or by Mozart is 0.50.
Option c.