GATE Computer Science (CS) 2021 Shift 2 Solved Paper

For two n-dimensional real vectors P and Q, the operation s(P, Q) is defined as follows:
$\mathit{s}\left(\mathit{P},\mathit{Q}\right)=\sum _{\mathit{i}=1}^{\mathit{n}}\left(\mathit{p}\left[\mathit{i}\right].\mathit{Q}\left[\mathit{i}\right]\right)$
Let L be a set of 10-dimensional non-zero vectors such that for every pair of distinct vectors P, Q ∈ L, s(P, Q) = 0. What is the maximum cardinality possible for the set L ?