= Solution
The acetylide attacks the less substituted terminal <epoxide> carbon by <SN2> ring opening. The C–O bond at that carbon breaks, leaving the oxygen attached to the original substituted <stereocentre>. Protonation gives $\mathrm{BnOCH_2CH(OH)CH_2C\equiv CMe}$. Dissolving-metal reduction then gives the E <alkene> and also cleaves the benzyl ether.
Thus \b[H is $\mathrm{HOCH_2CH(OH)CH_2CH=CHMe}$ with an E double bond], and its original epoxide-derived <stereocentre> is retained geometrically. No new tetrahedral <stereocentre> is formed: the attacked <epoxide> carbon becomes CH$_2$. The new stereochemical information is the \b[E <alkene> geometry]. Calling its secondary hydroxyl carbon “newly generated” would confuse changing its functional environment with creating a new <stereocentre>.
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