To solve this problem, we need to understand the relationship between the father's and the son's ages both in the past and in the future. Let's break it down step-by-step:

1. Let's denote the son's current age as S years.
2. Therefore, 3 years ago, his age would have been (S - 3) years.
3. Let the father's current age be F years.
4. Thus, 3 years ago, the father's age was (F - 3) years.
5. According to the problem, 3 years ago, the father's age was 40 years more than twice the son's age. This can be expressed by the equation: F - 3 = 2(S - 3) + 40.
6. Simplifying the equation:
   • F - 3 = 2S - 6 + 40
   • F - 3 = 2S + 34
   • F = 2S + 37
7. We need to find after how many years from now will the father's age be twice the son's age. Let this time in years be x years.
8. At that future time, the son's age will be (S + x) and the father's age will be (F + x).
9. According to the problem, at that future time, the father's age will be twice the son's age, so we set up the equation: F + x = 2(S + x).
10. Substituting F = 2S + 37 into the equation, we get:
    • 2S + 37 + x = 2(S + x)
    • 2S + 37 + x = 2S + 2x
    • 37 + x = 2x
    • 37 = x
11. Therefore, the father will be twice the son's age after 37 years.

Thus, the correct answer is 37.