40. Приведенная формула соответствует

The given formula is CH2=C(CH3)-CH2-CH3. This is an alkene. The longest carbon chain containing the double bond has four carbons (butene). The double bond starts at the second carbon. There is a methyl group attached to the second carbon. Therefore, the name is 2-methylbut-2-ene. Looking at the options, '2-метилбутену-1' is incorrect as the double bond is at position 2. 'Пентану' is an alkane. '2-метилбутану' is an alkane. The closest option is '2-метилбутену-1', but the numbering is incorrect. Let's re-examine the structure and options. The longest chain is 4 carbons. The double bond is between C2 and C3. A methyl group is on C2. So it's 2-methylbut-2-ene. None of the options perfectly match. However, if we consider the possibility of a typo in the question or options, and assume the double bond is at position 1, then it would be 2-methylbut-1-ene. Let's assume the option '2-метилбутену-1' is intended to represent this structure, despite the numbering discrepancy.

Answer: в) 2-метилбутену-1