Let's denote Ram's present age as \( R \) and his father's present age as \( F \).

According to the problem:
1. Ram's age is one-sixth of his father's age:
\[
R = \frac{1}{6}F
\]

2. The difference between their present ages is 35 years:
\[
F - R = 35
\]

Substitute \( R \) from the first equation into the second equation:
\[
F - \frac{1}{6}F = 35
\]

Combine like terms:
\[
\frac{5}{6}F = 35
\]

Solve for \( F \):
\[
F = 35 \times \frac{6}{5} = 42
\]


Ram's father's present age is 42 years.

The correct answer is B. 42 years.