= Solution
\b[C has a saturated backbone and pendant $\mathrm{CH_2OH}$ groups in its second block.] <Hydrogenation> converts every backbone $\mathrm{CH=CH}$ to $\mathrm{CH_2CH_2}$; <lithium aluminium hydride> then reduces each $\mathrm{CO_2Me}$ to $\mathrm{CH_2OH}$. The resulting connectivity is $\mathrm{[CH_2CH_2-C_5H_8]_{50}-[CH_2CH_2-C_5H_7(CH_2OH)]_{75}}$.
<Hydrogenation> removes local double-bond rigidity and commonly lowers the segmental barrier to motion, favouring a lower <glass transition temperature>. <Ester> reduction changes polarity and side-group volume, while the new hydroxyl groups introduce <hydrogen bonding>, which can raise the hydroxyl-rich block's <glass transition temperature> and strengthen segregation. These competing effects preclude a numerical transition shift or an unconditional direction for both transitions from structure alone.
The repeat-unit formulae after both operations are $\mathrm{C_7H_{12}}$ and $\mathrm{C_8H_{14}O}$. Taking standard atomic masses,
$$
\boxed{M_{n,\mathrm{repeat}}=50(96.173)+75(126.199)=1.4274\times10^4\ \mathrm{g\,mol^{-1}}.}
$$
This is \b[approximately 14.27 kg mol$^{-1}$ plus the net end-group mass]. The termination chemistry is unspecified, so a more precise whole-chain mass is not determined; the methyl group lost during <ester> reduction must not remain in the second repeat's mass.
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