To simplify the expression \( \frac{1}{4} + \frac{7}{20} \), we need to find a common denominator.
The denominators are 4 and 20. The least common multiple of 4 and 20 is 20.
Now we can convert \( \frac{1}{4} \) to have a denominator of 20:
\[ \frac{1}{4} = \frac{1 \times 5}{4 \times 5} = \frac{5}{20} \]
Now we can add the two fractions:
\[ \frac{5}{20} + \frac{7}{20} = \frac{5 + 7}{20} = \frac{12}{20} \]
Now we can simplify \( \frac{12}{20} \). We can divide both the numerator and the denominator by their greatest common divisor, which is 4:
\[ \frac{12 \div 4}{20 \div 4} = \frac{3}{5} \]
So the simplified expression is \( \frac{3}{5} \).
The correct answer is:
A. \( \frac{3}{5} \)