Member States may provide that the periods referred to in Article 2a(2) of this Directive do not apply in the following cases:

(a) if Directive 2014/25/EU or, where relevant, Directive 2014/23/EU does not require prior publication of a notice in the Official Journal of the European Union;

(b) if the only tenderer concerned within the meaning of Article 2a(2) of this Directive is the one who is awarded the contract and there are no candidates concerned;

(c) in the case of specific contracts based on a dynamic purchasing system as provided for in Article 52 of Directive 2014/25/EU.

If this derogation is invoked, Member States shall ensure that the contract is ineffective in accordance with Articles 2d and 2f of this Directive where:

- there is an infringement of Article 52(6) of Directive 2014/25/EU, and

- the contract value is estimated to be equal to or to exceed the thresholds set out in Article 15 of Directive 2014/25/EU.