Most of giotto's surviving works are:
a. frescoes
b. friezes
c. madonnas.
d. mosaics.

  A. frescoes

Most of Giotto's surviving works are Frescoes

Explanation:

The most significant of Giotto's enduring works are the frescoes he made for a little church in Padua known as the Arena Chapel or the Scrovegni Chapel (after the benefactor who dispatched the work). They delineate the life of the Virgin Mary and the life of Christ.

Giotto,The Kiss of Judas, Arena Chapel, 1304-1306. Figures and sensational methods in Giotto's most noteworthy work, the Arena Chapel in Padua, take the stand this isn't effectively comprehensible among enduring works of.