Correct option is (D) 120°
\(\because\) \(\angle A+\angle B+\angle C+\angle D\) \(=360^\circ\) (Sum of all interior angles in a quadrilateral is \(360^\circ)\)
\(\Rightarrow\) \(\angle D=360^\circ-\angle A-\angle B-\angle C\)
\(=360^\circ-70^\circ-110^\circ-60^\circ\) \((\because\angle A=70^\circ,\angle B=110^\circ,\angle C=60^\circ)\)
\(=360^\circ-240^\circ\)
\(=120^\circ\)
