Step 1: Plan
Test each relation with real bond lengths instead of memorised words.
Step 2: Size of atom
Take the hydrogen halides: H-F is 92 pm, H-Cl is 127 pm, H-Br is 141 pm and H-I is 161 pm. Atomic size grows down the group and the bond length grows with it. So bond length and atomic size move together, a direct relation.
Step 3: Multiplicity of bond
Take the carbon-carbon bonds: single 154 pm, double 134 pm, triple 120 pm. As the number of shared pairs rises, the nuclei sit closer. So bond length and multiplicity move in opposite directions, an inverse relation.
Step 4: Decide
The pair (direct, inverse) is option (A). Options with "inverse" for size or "direct" for multiplicity contradict the data above.
Final Answer:
Bond length is directly related to atomic size and inversely related to bond multiplicity, option (A).
\[ \boxed{\text{(I) direct, (II) inverse}} \]