Step 1: Identify Article 75 and the Doctrine of Pleasure.
Article 75 of the Indian Constitution deals with the appointment and tenure of the Council of Ministers; it incorporates the Doctrine of Pleasure borrowed from British constitutional law, where ministers serve at the sovereign's discretion.
Step 2: State Article 75(2) precisely.
Article 75(2) explicitly states: "The Ministers shall hold office during the pleasure of the President"; though the President acts on the Prime Minister's advice in practice, the constitutional language clearly places the "pleasure" with the President.
Step 3: Eliminate other options.
Ministers do not hold office at the PM's pleasure in constitutional language; there is no Speaker's pleasure or fixed 5-year ministerial term; "during pleasure of President" is the precise constitutional formulation under Article 75(2).
\[ \boxed{\text{During pleasure of President}} \]