The straight chain polymer is formed by

• A

  hydrolysis of $\left(\mathrm{CH}_3\right)_3 \mathrm{SiCl}$ followed by condensation polymerisation
• B

  hydrolysis of $\mathrm{CH}_3 \mathrm{SiCl}_3$ followed by condensation polymerisation
• C

  hydrolysis of $\left(\mathrm{CH}_3\right)_4 \mathrm{Si}$ by addition polymerisation
• Correct answer
  D

  hydrolysis of $\left(\mathrm{CH}_3\right)_2 \mathrm{SiCl}_2$ followed by condensation polymerisation

Solution

$\mathrm{RSiCl}_3$ (trichloro derivatives) on hydrolysis followed by condensation polymerisation yields branched chain silicones. Straight chain silanes are silicone oils. These are more stable at high temperature than mineral oils and have less tendency to thicken at low temperature.

Hence, the correct answer is option: 'D'.