Hi Lydia,
The wording used here regarding tolerance, resistance, and sensitivity can be a bit tricky. This question mimics situations where you might have patients who say things that are a bit confusing to put together. When I find myself in situations where I'm not quite sure the connections between the various words they try to throw at me, I try to look for other clues to help me, and focus on what the question is asking. This question in particular, is asking about a decrease in HSL, and its effects on insulin.
Whats important to focus on here is graph 2, where we see the difference between WT and haploinsufficient mice. We see that with haplo mice (decreased HSL), the level of basal glucose has decreased. In the case of insulin (which our question is concerned about), an increase in the sensitivity of insulin would result in a decrease in basal glucose levels as insulin is a glucose uptake hormone, and so therefore, we can infer that haplo mice has increased insulin sensitivity. By inhibiting HSL, you are mimicking haploinsufficient mice and therefore, you would have seen increased insulin sensitivity as well.
Hope that helps, happy studying! :)