Task: Sentiment_Analysis
user: 

 You are a helpful assistant. The assistant first thinks about the reasoning process in the mind by using Belief-Desire-Intention (BDI) framework and then provides the user with the answer. The reasoning process and answer are enclosed within <think> </think> and <answer> </answer> tags, respectively.  /nFor the BDI reasoning process, (1) Based on the User Review, starting with "customer believes", list the user's beliefs; then, based on the User Review and the definition of Reiss's 16 basic desires theory, list the user's desires; next, based on the listed beliefs, desires and User Review, starting with "customer intends", list the intentions; (2) Finally, based on the generated beliefs, desires and intentions, construct logically BDI reasoning process, and select the correct answer based on the BDI reasoning process and input. /nThe definition of Reiss's 16 Basic Desires Theory: 1. Acceptance - the need to be appreciated 2. Curiosity, the need to gain knowledge 3. Eating, the need for food 4. Family, the need to take care of one’s offspring 5. Honor, the need to be faithful to the customary values of an individual’s ethnic group, family or clan 6. Idealism, the need for social justice 7. Independence, the need to be distinct and self-reliant 8. Order, the need for prepared, established, and conventional environments 9. Physical activity, the need for work out of the body 10. Power, the need for control of will 11. Romance, the need for mating or sex 12. Saving, the need to accumulate something 13. Social contact, the need for relationship with others 14. Social status, the need for social significance 15. Tranquility, the need to be secure and protected 16. Vengeance, the need to strike back against another person/nNow the user gives an instruction that describes a task and ask you write a response that appropriately completes the request. After thinking, when you finally reach a conclusion, clearly state the BDI thinking process within <think> </think> firstly and then the answer (i.e., answer only letters in options) within <answer> </answer> tags.
Instruction: Assess the user's sentiment in the provided review and select the appropriate sentiment option from the list as the answer.

Input:
User Review: I just got this lens to replace or add to my Pentax M 50mm F1.7.  The M 1.7 is a nice quality lens taht produces some fantastic results, but without Auto Focus, it's a little hard to take pictures of children.  Many people say this FA f1.4 is a "little soft wide open" or "Pentax F/FA 50mm f1.7 is sharper wide open"--because of those rumors/posts I was debating on FA 1.4 or F 1.7  I am glad that I bought this 1.4.  I found some examples of images taken at same aperture value, both lenses at F2.0 or F1.8 and the FA 50mm f1.4 is much sharper.  So I don't know why so many people comparing wide open when F1.7 can't do 1.4??? you just don't have that option at all and that is the value I find in this little amazing lens.

I have uploaded a few pics to product image on amazon, take a look... (I am using it with my K-x)

Options:
A: very positive
B: positive
C: neutral
D: negative
E: very negative


<think>
Answer: A: very positive