Which of the following is an incorrect statement with respect to PCR technique?

Two oligonucleotide primers anneal to each of the two strands of DNA at their 3' complimentary ends.

Deoxyribonucleotide triphosphates are used raw material for the synthesis of new DNA strand.

A 17-25-nucleotides-long primer is needed to bind with the template.

The optimum temperature for polymerisation is ${90}^{\mathrm{o}}\mathrm{C}$