Oh, I didn't realize those were two different months. This makes this whole question invalid indeed, and even
@taowave wouldn't be able to answer it (as he wasn't able to answer any of these questions anyway). So OP @
mozung, you may want to contact TDA and tell them that question #14 seems invalid and doesn't have an answer, because with two different months sometimes the vega can be positive and other times negative.
Here is an example with positive Vega:
View attachment 261244
vs different months with negative Vega:
View attachment 261245
Everyone else here didn't even look at the questions and just bullshits about how standard they are, and much they know about Vega. Maybe they can provide the right answer