The probability that Sarah's husband will order her a three-course meal with ice-cream as dessert depends on a few factors.
1. If Sarah being a vegetarian means that she doesn't eat ice-cream due to it containing animal products, then the probability would be 0 because her husband wouldn't order her that dessert.
2. If Sarah's vegetarianism only pertains to avoiding meat and she's fine with dairy products like ice-cream, then we can calculate the probability based on the menu options and Sarah's preferences. For example, if there are 4 dessert options, including ice-cream, then the probability would be 1 out of 4, which is 0.25.
3. Without knowing the specific details of the menu and Sarah's preferences regarding ice-cream as a vegetarian, it's challenging to determine the exact probability. Therefore, based on the given options in the question, none of the provided probabilities align with a clear calculation based on the information provided.
In conclusion, without more information on Sarah's dietary restrictions and the menu options, it is difficult to determine the exact probability.
